Separate quiz logic from main function fo dedicated moduleHEADmaster

Signed-off-by: Filip Wandzio <contact@philw.dev>

13 files changed, 599 insertions, 206 deletions

diff --git a/.gitignore b/.gitignore
index d483172..8e37b1f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,7 +4,7 @@
 ### C++ ###
 # Prerequisites
 *.d
-
+build
 *.csv
 # Compiled Object files
 *.slo
diff --git a/.idea/codeStyles/Project.xml b/.idea/codeStyles/Project.xml
new file mode 100644
index 0000000..54584fe
--- /dev/null
+++ b/.idea/codeStyles/Project.xml
@@ -0,0 +1,106 @@
+<component name="ProjectCodeStyleConfiguration">
+  <code_scheme name="Project" version="173">
+    <option name="WRAP_WHEN_TYPING_REACHES_RIGHT_MARGIN" value="true" />
+    <RiderCodeStyleSettings>
+      <option name="/Default/CodeStyle/CodeFormatting/CppClangFormat/EnableClangFormatSupport/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/EditorConfig/EnableClangFormatSupport/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_BINARY_EXPRESSIONS_CHAIN/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_CALLS_CHAIN/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_EXPRESSION/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_FOR_STMT/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTIPLE_DECLARATION/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_TERNARY/@EntryValue" value="ALIGN_ALL" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/BLANK_LINES_AROUND_CLASS_DEFINITION/@EntryValue" value="1" type="int" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/KEEP_BLANK_LINES_IN_DECLARATIONS/@EntryValue" value="2" type="int" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/KEEP_BLANK_LINES_IN_CODE/@EntryValue" value="2" type="int" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/KEEP_USER_LINEBREAKS/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_CASE_FROM_SWITCH/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_COMMENT/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INT_ALIGN_EQ/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SIMPLE_BLOCK_STYLE/@EntryValue" value="DO_NOT_CHANGE" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_COMMA_IN_TEMPLATE_ARGS/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_COMMA_IN_TEMPLATE_PARAMS/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_FOR_SEMICOLON/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_FOR_SEMICOLON/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_UNARY_OPERATOR/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_ARRAY_ACCESS_BRACKETS/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_CAST_EXPRESSION_PARENTHESES/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_EMPTY_INITIALIZER_BRACES/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_EMPTY_METHOD_PARENTHESES/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_INITIALIZER_BRACES/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPECIAL_ELSE_IF_TREATMENT/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_CAST_EXPRESSION_PARENTHESES/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_AFTER_BINARY_OPSIGN/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_BEFORE_TERNARY_OPSIGNS/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/TYPE_DECLARATION_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/OTHER_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/CASE_BLOCK_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/BLANK_LINES_AROUND_FUNCTION_DECLARATION/@EntryValue" value="1" type="int" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/BLANK_LINES_AROUND_FUNCTION_DEFINITION/@EntryValue" value="1" type="int" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/PLACE_WHILE_ON_NEW_LINE/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/PLACE_ELSE_ON_NEW_LINE/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/PLACE_CATCH_ON_NEW_LINE/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/NAMESPACE_INDENTATION/@EntryValue" value="All" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_ARGUMENT/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_EXTENDS_LIST/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_PARAMETER/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_TYPE_ARGUMENT/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_TYPE_PARAMETER/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/BLANK_LINES_AROUND_DECLARATIONS/@EntryValue" value="0" type="int" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_ACCESS_SPECIFIERS_FROM_CLASS/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_CLASS_MEMBERS_FROM_ACCESS_SPECIFIERS/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/LINE_BREAK_AFTER_COLON_IN_MEMBER_INITIALIZER_LISTS/@EntryValue" value="ON_SINGLE_LINE" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/MEMBER_INITIALIZER_LIST_STYLE/@EntryValue" value="DO_NOT_CHANGE" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/PLACE_NAMESPACE_DEFINITIONS_ON_SAME_LINE/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_COLON_IN_BITFIELD_DECLARATOR/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_COLON_IN_BITFIELD_DECLARATOR/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_EXTENDS_COLON/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_EXTENDS_COLON/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_FOR_COLON/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_FOR_COLON/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_PTR_IN_DATA_MEMBER/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_PTR_IN_DATA_MEMBERS/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_PTR_IN_METHOD/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_PTR_IN_NESTED_DECLARATOR/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_REF_IN_DATA_MEMBER/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_REF_IN_DATA_MEMBERS/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_REF_IN_METHOD/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_PTR_IN_ABSTRACT_DECL/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_PTR_IN_DATA_MEMBER/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_PTR_IN_DATA_MEMBERS/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_PTR_IN_METHOD/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_REF_IN_ABSTRACT_DECL/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_REF_IN_DATA_MEMBER/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_REF_IN_DATA_MEMBERS/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_REF_IN_METHOD/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_TEMPLATE_ARGS/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_TEMPLATE_PARAMS/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BETWEEN_CLOSING_ANGLE_BRACKETS_IN_TEMPLATE_ARGS/@EntryValue" value="true" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_EMPTY_TEMPLATE_PARAMS/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_TEMPLATE_ARGS/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_TEMPLATE_PARAMS/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_DECLARATION_PARENTHESES/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_EMPTY_BLOCKS/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_BEFORE_INVOCATION_LPAR/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_AFTER_INVOCATION_LPAR/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_BEFORE_INVOCATION_RPAR/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_BEFORE_DECLARATION_LPAR/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_AFTER_DECLARATION_LPAR/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_BEFORE_DECLARATION_RPAR/@EntryValue" value="false" type="bool" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_ARGUMENTS_STYLE/@EntryValue" value="WRAP_IF_LONG" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_PARAMETERS_STYLE/@EntryValue" value="WRAP_IF_LONG" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/BREAK_TEMPLATE_DECLARATION/@EntryValue" value="LINE_BREAK" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/NAMESPACE_DECLARATION_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INVOCABLE_DECLARATION_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ANONYMOUS_METHOD_DECLARATION_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INITIALIZER_BRACES/@EntryValue" value="END_OF_LINE_NO_SPACE" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_STYLE/@EntryValue" value="Space" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_SIZE/@EntryValue" value="4" type="int" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/CONTINUOUS_LINE_INDENT/@EntryValue" value="Double" type="string" />
+      <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/TAB_WIDTH/@EntryValue" value="4" type="int" />
+    </RiderCodeStyleSettings>
+    <clangFormatSettings>
+      <option name="ENABLED" value="true" />
+    </clangFormatSettings>
+  </code_scheme>
+</component>
\ No newline at end of file
diff --git a/.idea/codeStyles/codeStyleConfig.xml b/.idea/codeStyles/codeStyleConfig.xml
new file mode 100644
index 0000000..79ee123
--- /dev/null
+++ b/.idea/codeStyles/codeStyleConfig.xml
@@ -0,0 +1,5 @@
+<component name="ProjectCodeStyleConfiguration">
+  <state>
+    <option name="USE_PER_PROJECT_SETTINGS" value="true" />
+  </state>
+</component>
\ No newline at end of file
diff --git a/build/exam b/build/exam
index 988b751..77b3548 100755
--- a/build/exam
+++ b/build/exam
diff --git a/build/test_questions b/build/test_questions
index 04dac40..bdf53be 100755
--- a/build/test_questions
+++ b/build/test_questions
diff --git a/include/questions.h b/include/questions.h
index 75bc751..95ce286 100644
--- a/include/questions.h
+++ b/include/questions.h
@@ -2,19 +2,19 @@
 #include <stddef.h>
 
 typedef struct {
-  char **general;
-  char **major;
-  size_t general_count;
-  size_t major_count;
+        char** general;
+        char** major;
+        size_t general_count;
+        size_t major_count;
 } QuestionSet;
 
 /**
  * Load questions from file.
  * Returns EXIT_SUCCESS or EXIT_FAILURE.
  */
-int load_questions(const char *filename, QuestionSet *qs);
+int load_questions(const char* filename, QuestionSet* qs);
 
 /**
  * Free all allocated memory in QuestionSet.
  */
-void free_questions(QuestionSet *qs);
+void free_questions(QuestionSet* qs);
diff --git a/include/quiz.h b/include/quiz.h
new file mode 100644
index 0000000..db69367
--- /dev/null
+++ b/include/quiz.h
@@ -0,0 +1,34 @@
+//
+// Created by philw on 01/03/2026.
+//
+
+#pragma once
+
+#include "../include/questions.h"
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+
+#define PERCENT_MULTIPLIER 100.0
+#define SCORE_FORMAT "Score: %zu/%zu (%.1f%%)\n"
+
+// ------------------------
+// Quiz state
+// ------------------------
+typedef struct {
+        QuestionSet questions;
+        FILE* csv;
+        unsigned int seed;
+        size_t total_answered;
+        size_t total_correct;
+        int time_limit;
+} QuizSession;
+
+// ------------------------
+// Quiz functions
+// ------------------------
+bool initialize_quiz_session(QuizSession* session);
+bool quiz_iteration(QuizSession* session);
+void print_score(size_t correct, size_t total);
+void print_final_score(const QuizSession* session);
+void cleanup_session(QuizSession* session);
diff --git a/include/utils.h b/include/utils.h
index 74c0ca1..08895c0 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -1,8 +1,30 @@
 #pragma once
+
+#include <stdbool.h>
 #include <stddef.h>
 
+/** Print a horizontal separator line */
 void print_line(void);
-void wait_enter(const char *msg);
-char ask_yes_no(const char *msg);
-void now_str(char *buf, size_t size);
-size_t rand_index(size_t max);
+
+/** Pause until the user presses ENTER */
+void wait_for_enter(const char* prompt);
+
+/** Ask a yes/no question and return boolean */
+bool ask_yes_no(const char* prompt);
+
+/**
+ * Get the current timestamp for recording when a question was answered
+ *
+ * @param answer_time_buffer Buffer to store the formatted timestamp
+ * @param buffer_capacity Size of the buffer in bytes
+ */
+void get_answer_timestamp(char* answer_time_buffer, size_t buffer_capacity);
+
+/**
+ * Get a random question index in the quiz (thread-safe)
+ *
+ * @param seed Pointer to an unsigned int seed (per-thread)
+ * @param total_questions Number of questions in the current quiz session
+ * @return Random index in the range [0, total_questions-1]
+ */
+size_t get_random_question_index(unsigned int* seed, size_t total_questions);
diff --git a/src/main.c b/src/main.c
index 33d4b39..f69d734 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,83 +1,15 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include <time.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-
-#include "questions.h"
-#include "utils.h"
-
-int main(void) {
-    srand((unsigned)time(NULL));
-
-    // utwórz katalog data/ jeśli nie istnieje
-    struct stat st = {0};
-    if (stat("data", &st) == -1) {
-#ifdef _WIN32
-        _mkdir("data");
-#else
-        mkdir("data", 0755);
-#endif
-    }
-
-    QuestionSet qs;
-    if (load_questions("data/questions.txt", &qs) != EXIT_SUCCESS) {
-        fprintf(stderr, "Error: cannot load questions file\n");
-        return EXIT_FAILURE;
-    }
-
-    FILE *csv = fopen("data/results.csv", "a");
-    if (!csv) {
-        perror("CSV open");
-        free_questions(&qs);
-        return EXIT_FAILURE;
-    }
-
-    int limit = 0;
-    printf("Time limit (sec, 0 = unlimited): ");
-    if (scanf("%d", &limit) != 1) limit = 0;
-    wait_enter(NULL);
-
-    size_t total = 0, correct = 0;
-    char cont = 'y';
-
-    while (cont == 'y' || cont == 'Y') {
-        const char *g = qs.general[rand_index(qs.general_count)];
-        const char *m = qs.major[rand_index(qs.major_count)];
-
-        print_line();
-        printf("GENERAL:\n%s\n\nMAJOR:\n%s\n", g, m);
-        print_line();
+#include "../include/quiz.h" // QuizSession and functions
 
-        wait_enter("Press ENTER to start...");
-        time_t start = time(NULL);
-
-        wait_enter("Press ENTER when done...");
-        double duration = difftime(time(NULL), start);
-
-        if (limit > 0 && duration > limit)
-            printf("Time exceeded!\n");
-
-        char ans = ask_yes_no("Correct? (y/n): ");
-        if (ans == 'y' || ans == 'Y') correct++;
-        total++;
-
-        char ts[32];
-        now_str(ts, sizeof(ts));
-        fprintf(csv, "\"%s\",\"%s\",\"%s\",%c,%.0f\n", ts, g, m, ans, duration);
-
-        printf("Score: %zu/%zu (%.1f%%)\n",
-               correct, total,
-               total ? (double)correct / total * 100 : 0.0);
-
-        cont = ask_yes_no("Next? (y/n): ");
-    }
-
-    printf("\nSession score: %.1f%%\n",
-           total ? (double)correct / total * 100 : 0.0);
-
-    fclose(csv);
-    free_questions(&qs);
+#include <stdlib.h>
 
-    return EXIT_SUCCESS;
-}
+int main(void)
+{
+        QuizSession session;
+        if (!initialize_quiz_session(&session))
+                return EXIT_FAILURE;
+        while (quiz_iteration(&session)) {
+        }
+        print_final_score(&session);
+        cleanup_session(&session);
+        return EXIT_SUCCESS;
+}
\ No newline at end of file
diff --git a/src/questions.c b/src/questions.c
index 88671a7..491c106 100644
--- a/src/questions.c
+++ b/src/questions.c
@@ -5,88 +5,94 @@
 
 #define MAX_LINE 512
 
-static int add_question(char ***arr, size_t *count, const char *text) {
-  char **tmp = realloc(*arr, (*count + 1) * sizeof(char *));
-  if (!tmp)
-    return EXIT_FAILURE;
-  *arr = tmp;
-
-  (*arr)[*count] = malloc(strlen(text) + 1);
-  if (!(*arr)[*count])
-    return EXIT_FAILURE;
-
-  strcpy((*arr)[*count], text);
-  (*count)++;
-  return EXIT_SUCCESS;
+static int add_question(char*** arr, size_t* count, const char* text)
+{
+        char** tmp = realloc(*arr, (*count + 1) * sizeof(char*));
+        if (!tmp)
+                return EXIT_FAILURE;
+        *arr = tmp;
+
+        (*arr)[*count] = malloc(strlen(text) + 1);
+        if (!(*arr)[*count])
+                return EXIT_FAILURE;
+
+        strcpy((*arr)[*count], text);
+        (*count)++;
+        return EXIT_SUCCESS;
 }
 
-int load_questions(const char *filename, QuestionSet *qs) {
-  if (!filename || !qs)
-    return EXIT_FAILURE;
-
-  FILE *f = fopen(filename, "r");
-  if (!f)
-    return EXIT_FAILURE;
-
-  qs->general = NULL;
-  qs->major = NULL;
-  qs->general_count = 0;
-  qs->major_count = 0;
-
-  char line[MAX_LINE];
-  enum { NONE, GENERAL, MAJOR } mode = NONE;
-
-  while (fgets(line, sizeof(line), f)) {
-    line[strcspn(line, "\n")] = '\0';
-    if (line[0] == '\0')
-      continue;
-
-    if (strcmp(line, "#GENERAL") == 0) {
-      mode = GENERAL;
-      continue;
-    }
-    if (strcmp(line, "#MAJOR") == 0) {
-      mode = MAJOR;
-      continue;
-    }
-
-    int res = EXIT_FAILURE;
-    switch (mode) {
-    case GENERAL:
-      res = add_question(&qs->general, &qs->general_count, line);
-      break;
-    case MAJOR:
-      res = add_question(&qs->major, &qs->major_count, line);
-      break;
-    default:
-      continue; // ignore lines before section
-    }
-
-    if (res != EXIT_SUCCESS) {
-      fclose(f);
-      free_questions(qs);
-      return EXIT_FAILURE;
-    }
-  }
-
-  fclose(f);
-  return (qs->general_count && qs->major_count) ? EXIT_SUCCESS : EXIT_FAILURE;
+int load_questions(const char* filename, QuestionSet* qs)
+{
+        if (!filename || !qs)
+                return EXIT_FAILURE;
+
+        FILE* f = fopen(filename, "r");
+        if (!f)
+                return EXIT_FAILURE;
+
+        qs->general = NULL;
+        qs->major = NULL;
+        qs->general_count = 0;
+        qs->major_count = 0;
+
+        char line[MAX_LINE];
+        enum { NONE, GENERAL, MAJOR } mode = NONE;
+
+        while (fgets(line, sizeof(line), f)) {
+                line[strcspn(line, "\n")] = '\0';
+                if (line[0] == '\0')
+                        continue;
+
+                if (strcmp(line, "#GENERAL") == 0) {
+                        mode = GENERAL;
+                        continue;
+                }
+                if (strcmp(line, "#MAJOR") == 0) {
+                        mode = MAJOR;
+                        continue;
+                }
+
+                int res = EXIT_FAILURE;
+                switch (mode) {
+                        case GENERAL:
+                                res = add_question(
+                                    &qs->general, &qs->general_count, line);
+                                break;
+                        case MAJOR:
+                                res = add_question(
+                                    &qs->major, &qs->major_count, line);
+                                break;
+                        default:
+                                continue;
+                }
+
+                if (res != EXIT_SUCCESS) {
+                        fclose(f);
+                        free_questions(qs);
+                        return EXIT_FAILURE;
+                }
+        }
+
+        fclose(f);
+        return (qs->general_count && qs->major_count) ? EXIT_SUCCESS
+                                                      : EXIT_FAILURE;
 }
 
-void free_questions(QuestionSet *qs) {
-  if (!qs)
-    return;
+void free_questions(QuestionSet* qs)
+{
+        if (!qs)
+                return;
 
-  for (size_t i = 0; i < qs->general_count; i++)
-    free(qs->general[i]);
-  for (size_t i = 0; i < qs->major_count; i++)
-    free(qs->major[i]);
+        for (size_t i = 0; i < qs->general_count; i++)
+                free(qs->general[i]);
+        for (size_t i = 0; i < qs->major_count; i++)
+                free(qs->major[i]);
 
-  free(qs->general);
-  free(qs->major);
+        free(qs->general);
+        free(qs->major);
 
-  qs->general = NULL;
-  qs->major = NULL;
-  qs->general_count = 0;
-  qs->major_count = 0;
+        qs->general = NULL;
+        qs->major = NULL;
+        qs->general_count = 0;
+        qs->major_count = 0;
 }
diff --git a/src/quiz.c b/src/quiz.c
new file mode 100644
index 0000000..7bc31b2
--- /dev/null
+++ b/src/quiz.c
@@ -0,0 +1,203 @@
+#include "../include/quiz.h"
+#include "../include/utils.h"
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <time.h>
+
+#define INPUT_BUFFER_SIZE 64
+#define QUIZ_DATA_DIRECTORY "data"
+#define QUESTIONS_FILE_NAME "questions.txt"
+#define RESULTS_FILE_NAME "results.csv"
+#define CSV_TIMESTAMP_BUFFER 32
+#define FILE_PATH_BUFFER 256
+#define PERMISSIONS_DATA_DIRECTORY 0755
+#define TIME_UNLIMITED 0
+#define BASE_VALUE 10
+
+static const char* START_PROMPT = "Press ENTER to start...";
+static const char* DONE_PROMPT = "Press ENTER when done...";
+static const char* TIME_LIMIT_PROMPT = "Time limit (sec, 0 = unlimited): ";
+static const char* CORRECT_PROMPT = "Correct? (y/n): ";
+static const char* NEXT_QUESTION_PROMPT = "Next? (y/n): ";
+static const char* TIME_EXCEEDED_MESSAGE = "Time exceeded!\n";
+static const char* CSV_OPEN_ERROR_MESSAGE = "CSV open";
+static const char* QUESTIONS_LOAD_ERROR = "Error: cannot load questions file\n";
+static const char* DATA_DIR_ERROR = "Error: cannot create data directory\n";
+
+static bool ensure_data_directory_exists(void)
+{
+        struct stat st = {0};
+        if (stat(QUIZ_DATA_DIRECTORY, &st) == -1) {
+#ifdef _WIN32
+                return _mkdir(QUIZ_DATA_DIRECTORY) == 0;
+#else
+                return mkdir(QUIZ_DATA_DIRECTORY, PERMISSIONS_DATA_DIRECTORY)
+                       == 0;
+#endif
+        }
+        return true;
+}
+
+static int read_time_limit(void)
+{
+        char buffer[INPUT_BUFFER_SIZE];
+        printf("%s", TIME_LIMIT_PROMPT);
+
+        if (!fgets(buffer, sizeof buffer, stdin))
+                return TIME_UNLIMITED;
+
+        errno = 0;
+        char* end = NULL;
+        long value = strtol(buffer, &end, BASE_VALUE);
+
+        if (errno == ERANGE || end == buffer)
+                return TIME_UNLIMITED;
+        if (value < 0)
+                value = 0;
+        if (value > INT_MAX)
+                value = INT_MAX;
+
+        return (int)value;
+}
+
+static void write_csv_result(FILE* csv,
+                             const char* timestamp,
+                             const char* general_q,
+                             const char* major_q,
+                             const bool correct_answer,
+                             const double duration)
+{
+        static const char* CSV_FORMAT = "\"%s\",\"%s\",\"%s\",%c,%.0f\n";
+        fprintf(csv,
+                CSV_FORMAT,
+                timestamp,
+                general_q,
+                major_q,
+                correct_answer ? 'y' : 'n',
+                duration);
+}
+
+void print_score(const size_t correct, size_t total)
+{
+        double percentage = 0.0;
+        if (total != 0)
+                percentage = (double)correct / total * PERCENT_MULTIPLIER;
+
+        printf(SCORE_FORMAT, correct, total, percentage);
+}
+
+void print_final_score(const QuizSession* session)
+{
+        double final_percentage = 0.0;
+        if (session->total_answered > 0)
+                final_percentage = (double)session->total_correct
+                                   / session->total_answered
+                                   * PERCENT_MULTIPLIER;
+
+        printf("\nSession score: %.1f%%\n", final_percentage);
+}
+
+// ------------------------
+// Initialization & Cleanup
+// ------------------------
+bool initialize_quiz_session(QuizSession* session)
+{
+        session->seed = (unsigned int)time(NULL);
+        srand(session->seed);
+
+        if (!ensure_data_directory_exists()) {
+                fprintf(stderr, "%s", DATA_DIR_ERROR);
+                return false;
+        }
+
+        char questions_path[FILE_PATH_BUFFER];
+        snprintf(questions_path,
+                 sizeof questions_path,
+                 "%s/%s",
+                 QUIZ_DATA_DIRECTORY,
+                 QUESTIONS_FILE_NAME);
+
+        char results_path[FILE_PATH_BUFFER];
+        snprintf(results_path,
+                 sizeof results_path,
+                 "%s/%s",
+                 QUIZ_DATA_DIRECTORY,
+                 RESULTS_FILE_NAME);
+
+        if (load_questions(questions_path, &session->questions)
+            != EXIT_SUCCESS) {
+                fprintf(stderr, "%s", QUESTIONS_LOAD_ERROR);
+                return false;
+        }
+
+        session->csv = fopen(results_path, "a");
+        if (!session->csv) {
+                perror(CSV_OPEN_ERROR_MESSAGE);
+                free_questions(&session->questions);
+                return false;
+        }
+
+        session->total_answered = 0;
+        session->total_correct = 0;
+        session->time_limit = read_time_limit();
+
+        return true;
+}
+
+void cleanup_session(QuizSession* session)
+{
+        fclose(session->csv);
+        free_questions(&session->questions);
+}
+
+// ------------------------
+// Single Quiz Iteration
+// ------------------------
+bool quiz_iteration(QuizSession* session)
+{
+        const size_t general_index = get_random_question_index(
+            &session->seed, session->questions.general_count);
+        const size_t major_index = get_random_question_index(
+            &session->seed, session->questions.major_count);
+
+        const char* general_question =
+            session->questions.general[general_index];
+        const char* major_question = session->questions.major[major_index];
+
+        print_line();
+        printf(
+            "GENERAL:\n%s\n\nMAJOR:\n%s\n", general_question, major_question);
+        print_line();
+
+        wait_for_enter(START_PROMPT);
+        const time_t start_time = time(NULL);
+
+        wait_for_enter(DONE_PROMPT);
+        const double duration_seconds = difftime(time(NULL), start_time);
+
+        if (session->time_limit > 0 && duration_seconds > session->time_limit)
+                printf("%s", TIME_EXCEEDED_MESSAGE);
+
+        const bool correct = ask_yes_no(CORRECT_PROMPT);
+        if (correct)
+                session->total_correct++;
+        session->total_answered++;
+
+        char timestamp[CSV_TIMESTAMP_BUFFER];
+        get_answer_timestamp(timestamp, sizeof timestamp);
+
+        write_csv_result(session->csv,
+                         timestamp,
+                         general_question,
+                         major_question,
+                         correct,
+                         duration_seconds);
+
+        print_score(session->total_correct, session->total_answered);
+
+        return ask_yes_no(NEXT_QUESTION_PROMPT);
+}
diff --git a/src/utils.c b/src/utils.c
index c139929..2e26e8e 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -1,34 +1,117 @@
 #include "utils.h"
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
 
-void print_line(void) {
-  printf("--------------------------------------------------\n");
+#define SEPARATOR_CHAR '-'
+#define SEPARATOR_WIDTH 50
+#define NEWLINE_CHAR '\n'
+#define INPUT_BUFFER_SIZE 16
+#define TIME_FORMAT_STRING "%Y-%m-%d %H:%M:%S"
+#define ASK_YES_NO_PROMPT "Please enter 'y' or 'n': "
+
+/** Clear leftover input from stdin */
+static void flush_stdin(void)
+{
+        int input_char;
+        do
+                input_char = getchar();
+        while (input_char != NEWLINE_CHAR && input_char != EOF);
+}
+
+/** Print a horizontal separator line for the quiz UI */
+static void print_separator_line(void)
+{
+        for (size_t current_column = 0; current_column < SEPARATOR_WIDTH;
+             ++current_column)
+                putchar(SEPARATOR_CHAR);
+
+        putchar(NEWLINE_CHAR);
 }
 
-void wait_enter(const char *msg) {
-  if (msg)
-    printf("%s", msg);
-  int c;
-  while ((c = getchar()) != '\n' && c != EOF)
-    ;
+/** Print a horizontal separator line */
+void print_line(void)
+{
+        print_separator_line();
 }
 
-char ask_yes_no(const char *msg) {
-  char c = 'n';
-  printf("%s", msg);
-  if (scanf(" %c", &c) != 1)
-    c = 'n';
-  int flush;
-  while ((flush = getchar()) != '\n' && flush != EOF)
-    ;
-  return c;
+/**
+ * Pause until the user presses ENTER
+ *
+ * @param prompt Optional message to display before waiting
+ */
+void wait_for_enter(const char* prompt)
+{
+        if (prompt != NULL)
+                fputs(prompt, stdout);
+
+        flush_stdin();
+}
+
+/**
+ * Ask a yes/no question and return a boolean answer
+ *
+ * @param prompt Question message to display
+ * @return true if user answered 'y' or 'Y', false if 'n', default false
+ */
+bool ask_yes_no(const char* prompt)
+{
+        char input_line[INPUT_BUFFER_SIZE];
+
+        while (1) {
+                if (prompt != NULL)
+                        fputs(prompt, stdout);
+
+                if (fgets(input_line, sizeof(input_line), stdin) == NULL)
+                        return false;
+
+                const char first_char = input_line[0];
+
+                if (first_char == 'y' || first_char == 'Y')
+                        return true;
+
+                if (first_char == 'n' || first_char == 'N')
+                        return false;
+
+                fputs(ASK_YES_NO_PROMPT, stdout);
+        }
 }
 
-void now_str(char *buf, size_t size) {
-  time_t t = time(NULL);
-  strftime(buf, size, "%Y-%m-%d %H:%M:%S", localtime(&t));
+/**
+ * Get the current timestamp for recording when a question was answered
+ *
+ * @param answer_time_buffer Buffer to store the formatted timestamp
+ * @param buffer_capacity Size of the buffer in bytes
+ */
+void get_answer_timestamp(char* answer_time_buffer,
+                          const size_t buffer_capacity)
+{
+        if (answer_time_buffer == NULL || buffer_capacity == 0)
+                return;
+
+        const time_t current_time = time(NULL);
+        const struct tm* local_time = localtime(&current_time);
+        if (local_time != NULL)
+                strftime(answer_time_buffer,
+                         buffer_capacity,
+                         TIME_FORMAT_STRING,
+                         local_time);
 }
 
-size_t rand_index(size_t max) { return max ? (size_t)(rand() % max) : 0; }
+/**
+ * Get a random question index in the quiz (thread-safe)
+ *
+ * @param seed Pointer to an unsigned int seed (per-thread)
+ * @param total_questions Number of questions in the current quiz session
+ * @return Random index in the range [0, total_questions-1]
+ */
+size_t get_random_question_index(unsigned int* seed,
+                                 const size_t total_questions)
+{
+        if (total_questions == 0 || seed == NULL)
+                return 0;
+
+        const unsigned long random_value = (unsigned long)rand_r(seed);
+        return random_value % total_questions;
+}
diff --git a/tests/test_questions.c b/tests/test_questions.c
index c605c1a..334ab86 100644
--- a/tests/test_questions.c
+++ b/tests/test_questions.c
@@ -1,24 +1,26 @@
-#include "questions.h"
+#include "../include/questions.h"
 #include <stdio.h>
 #include <stdlib.h>
 
-int main(void) {
-  QuestionSet qs;
+int main(void)
+{
+        QuestionSet qs;
 
-  if (load_questions("data/questions.txt", &qs) != EXIT_SUCCESS) {
-    fprintf(stderr, "TEST FAILED: cannot load file\n");
-    return EXIT_FAILURE;
-  }
+        if (load_questions("data/questions.txt", &qs) != EXIT_SUCCESS) {
+                fprintf(stderr, "TEST FAILED: cannot load file\n");
+                return EXIT_FAILURE;
+        }
 
-  if (qs.general_count == 0 || qs.major_count == 0) {
-    fprintf(stderr, "TEST FAILED: empty sets\n");
-    free_questions(&qs);
-    return EXIT_FAILURE;
-  }
+        if (qs.general_count == 0 || qs.major_count == 0) {
+                fprintf(stderr, "TEST FAILED: empty sets\n");
+                free_questions(&qs);
+                return EXIT_FAILURE;
+        }
 
-  printf("TEST OK: loaded %zu general, %zu major\n", qs.general_count,
-         qs.major_count);
+        printf("TEST OK: loaded %zu general, %zu major\n",
+               qs.general_count,
+               qs.major_count);
 
-  free_questions(&qs);
-  return EXIT_SUCCESS;
+        free_questions(&qs);
+        return EXIT_SUCCESS;
 }