all problems solved

Makefile

@@ -15,8 +15,6 @@ all: $(PROGRAMS)
 # -----------------------
 # Lab 1
 # -----------------------
-lab1: $(BUILD_DIR)/hello $(BUILD_DIR)/calculator $(BUILD_DIR)/formats
-
 $(BUILD_DIR)/hello: $(SRC_DIR)/hello.c
 	@mkdir -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
@@ -29,11 +27,13 @@ $(BUILD_DIR)/formats: $(SRC_DIR)/format_specifiers.c
 	@mkdir -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
 
+hello: $(BUILD_DIR)/hello
+calculator: $(BUILD_DIR)/calculator
+formats: $(BUILD_DIR)/formats
+
 # -----------------------
 # Lab 2
 # -----------------------
-lab2: $(BUILD_DIR)/lab2_1 $(BUILD_DIR)/lab2_2 $(BUILD_DIR)/lab2_3
-
 $(BUILD_DIR)/lab2_1: $(SRC_DIR)/lab2_1.c
 	@mkdir -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
@@ -46,11 +46,11 @@ $(BUILD_DIR)/lab2_3: $(SRC_DIR)/lab2_3.c
 	@mkdir -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
 
+lab2: $(BUILD_DIR)/lab2_1 $(BUILD_DIR)/lab2_2 $(BUILD_DIR)/lab2_3
+
 # -----------------------
 # Lab 3
 # -----------------------
-lab3: $(BUILD_DIR)/lab3_task1 $(BUILD_DIR)/lab3_task2 $(BUILD_DIR)/lab3_task3
-
 $(BUILD_DIR)/lab3_task1: $(SRC_DIR)/lab3_task1.c
 	@mkdir -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
@@ -63,11 +63,11 @@ $(BUILD_DIR)/lab3_task3: $(SRC_DIR)/lab3_task3.c
 	@mkdir -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
 
+lab3: $(BUILD_DIR)/lab3_task1 $(BUILD_DIR)/lab3_task2 $(BUILD_DIR)/lab3_task3
+
 # -----------------------
 # Lab 4
 # -----------------------
-lab4: $(BUILD_DIR)/week4_1_dynamic_array $(BUILD_DIR)/week4_2_struct_student $(BUILD_DIR)/week4_3_struct_database
-
 $(BUILD_DIR)/week4_1_dynamic_array: $(SRC_DIR)/week4_1_dynamic_array.c
 	@mkdir -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
@@ -80,6 +80,8 @@ $(BUILD_DIR)/week4_3_struct_database: $(SRC_DIR)/week4_3_struct_database.c
 	@mkdir -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
 
+lab4: $(BUILD_DIR)/week4_1_dynamic_array $(BUILD_DIR)/week4_2_struct_student $(BUILD_DIR)/week4_3_struct_database
+
 # -----------------------
 # Run targets
 # -----------------------
@@ -119,25 +121,21 @@ run-week4_2_struct_student: $(BUILD_DIR)/week4_2_struct_student
 run-week4_3_struct_database: $(BUILD_DIR)/week4_3_struct_database
 	./$(BUILD_DIR)/week4_3_struct_database
 
-# Run all tasks in Lab 2
 run-lab2: lab2
 	./$(BUILD_DIR)/lab2_1
 	./$(BUILD_DIR)/lab2_2
 	./$(BUILD_DIR)/lab2_3
 
-# Run all tasks in Lab 3
 run-lab3: lab3
 	./$(BUILD_DIR)/lab3_task1
 	./$(BUILD_DIR)/lab3_task2
 	./$(BUILD_DIR)/lab3_task3
 
-# Run all tasks in Lab 4
 run-lab4: lab4
 	./$(BUILD_DIR)/week4_1_dynamic_array
 	./$(BUILD_DIR)/week4_2_struct_student
 	./$(BUILD_DIR)/week4_3_struct_database
 
-# Run all labs (Lab 1 → Lab 4)
 run-all: all
 	./$(BUILD_DIR)/hello
 	./$(BUILD_DIR)/calculator

src/hello.c

@@ -3,7 +3,7 @@
 
 int main(int argc, char *argv[]) {
   // This is your first C program my friend
-  printf("Hello, RTU World from C Lab in 2025!\n");
+  printf("Hello from Ilham! \n");
   printf("You passed %d argument(s).\n", argc - 1);
   for (int i = 1; i < argc; ++i) {
     printf("  arg[%d] = %s\n", i, argv[i]);

src/lab2_1.c

@@ -4,25 +4,32 @@
     Task:
     Write a function `int sum_to_n(int n)` that computes
     the sum of all integers from 1 up to n using a for loop.
-
-    In main():
-      - Ask user for a positive integer n
-      - If n < 1, print an error
-      - Otherwise, call sum_to_n and print the result
 */
 
 int sum_to_n(int n) {
-    // TODO: implement sum with a for loop
-    return 0; // placeholder
+  int sum = 0;
+  for (int i = 1; i <= n; i++) {
+    sum += i;
+  }
+  return sum;
 }
 
 int main(void) {
-    int n;
+  int n;
+
+  printf("Enter a positive integer n: ");
+  if (scanf("%d", &n) != 1) {
+    printf("Error: Invalid input.\n");
+    return 1;
+  }
 
-    printf("Enter a positive integer n: ");
-    scanf("%d", &n);
+  if (n < 1) {
+    printf("Error: n must be >= 1\n");
+    return 1;
+  }
 
-    // TODO: validate input, call function, and print result
+  int result = sum_to_n(n);
+  printf("Sum from 1 to %d = %d\n", n, result);
 
-    return 0;
+  return 0;
 }

src/lab2_2.c

@@ -8,21 +8,43 @@
     In main():
       - Ask user for an integer n
       - If n is negative, print an error and exit
-      - Otherwise, call factorial and print the result
+      - Otherwise, call factorial and print the result.
 */
 
 long long factorial(int n) {
-    // TODO: compute factorial iteratively
-    return 1; // placeholder
+  long long result = 1;
+  for (int i = 1; i <= n; i++) {
+    result *= i;  // faktorial: n * (n-1) * ... * 1
+  }
+  return result;
 }
 
 int main(void) {
-    int n;
+  int n;
 
-    printf("Enter a non-negative integer n: ");
-    scanf("%d", &n);
+  printf("Enter a non-negative integer n: ");
+  scanf("%d", &n);
 
-    // TODO: validate input, call function, print result
+  if (n < 0) {
+    printf("Error: n must be >= 0\n");
+  } else {
+    long long fact = factorial(n);
+    printf("%d! = %lld\n", n, fact);
+  }
 
-    return 0;
+  return 0;
+
+  // TODO: compute factorial iteratively
+  return 1;  // placeholder
+}
+
+int main(void) {
+  int n;
+
+  printf("Enter a non-negative integer n: ");
+  scanf("%d", &n);
+
+  // TODO: validate input, call function, print result
+
+  return 0;
 }

src/lab2_3.c

@@ -1,3 +1,5 @@
+
+#include <math.h>  // for sqrt function
 #include <stdio.h>
 
 /*
@@ -12,17 +14,48 @@
 */
 
 int is_prime(int n) {
-    // TODO: check if n is prime using loop up to sqrt(n)
-    return 0; // placeholder
+  // TODO: check if n is prime using loop up to sqrt(n)
+  if (n < 2) return 0;  // numbers less than 2 are not prime
+  for (int i = 2; i <= sqrt(n); i++) {
+    if (n % i == 0) {
+      return 0;  // found a divisor → not prime
+    }
+  }
+  return 1;  // no divisors found → prime
+}
+
+int main(void) {
+  int n;
+
+  printf("Enter an integer n (>= 2): ");
+  scanf("%d", &n);
+
+  // TODO: validate input and print all primes up to n
+  if (n < 2) {
+    printf("Error: n must be >= 2\n");
+    return 1;
+  }
+
+  printf("Prime numbers up to %d:\n", n);
+  for (int i = 2; i <= n; i++) {
+    if (is_prime(i)) {
+      printf("%d ", i);
+    }
+  }
+  printf("\n");
+
+  return 0;
+  // TODO: check if n is prime using loop up to sqrt(n)
+  return 0;  // placeholder
 }
 
 int main(void) {
-    int n;
+  int n;
 
-    printf("Enter an integer n (>= 2): ");
-    scanf("%d", &n);
+  printf("Enter an integer n (>= 2): ");
+  scanf("%d", &n);
 
-    // TODO: validate input and print all primes up to n
+  // TODO: validate input and print all primes up to n.
 
-    return 0;
+  return 0;
 }

src/lab3_task1.c

@@ -1,6 +1,6 @@
 /*
  * Lab 3, Task 1
- * Student Name, Student ID
+ * Student Name:Ilham Dosdiyev, Student ID: 241ADB018
  *
  * Implement array algorithms:
  *   - find minimum value
@@ -21,8 +21,8 @@
  *   avg = array_avg(arr, 5); // 3.0
  */
 
-#include <stdio.h>
 #include <limits.h>
+#include <stdio.h>
 
 // Function prototypes
 int array_min(int arr[], int size);
@@ -31,40 +31,48 @@ int array_sum(int arr[], int size);
 float array_avg(int arr[], int size);
 
 int main(void) {
-    int arr[] = {10, 20, 5, 30, 15};
-    int size = 5;
+  int arr[] = {10, 20, 5, 30, 15};
+  int size = 5;
 
-    printf("Min: %d\n", array_min(arr, size));
-    printf("Max: %d\n", array_max(arr, size));
-    printf("Sum: %d\n", array_sum(arr, size));
-    printf("Avg: %.2f\n", array_avg(arr, size));
+  printf("Min: %d\n", array_min(arr, size));
+  printf("Max: %d\n", array_max(arr, size));
+  printf("Sum: %d\n", array_sum(arr, size));
+  printf("Avg: %.2f\n", array_avg(arr, size));
 
-    return 0;
+  return 0;
 }
 
 // Implement functions below
 int array_min(int arr[], int size) {
-    // TODO: return smallest element
-    int my_min = INT_MAX; //set to max infinity
-    for (int i=0;i<size;i++) {
-        if (my_min > arr[i]) {
-            my_min = arr[i];
-        }
+  // TODO: return smallest element
+  int my_min = INT_MAX;  // set to max infinity
+  for (int i = 0; i < size; i++) {
+    if (my_min > arr[i]) {
+      my_min = arr[i];
     }
-    return my_min; // placeholder
+  }
+  return my_min;
 }
 
 int array_max(int arr[], int size) {
-    // TODO: return largest element
-    return 0; // placeholder
+  int max_num = INT_MIN;
+  for (int i = 0; i < size; i++) {
+    if (arr[i] > max_num) {
+      max_num = arr[i];
+    }
+  }
+  return max_num;
 }
 
 int array_sum(int arr[], int size) {
-    // TODO: return sum of elements
-    return 0; // placeholder
+  int sum = 0;
+  for (int i = 0; i < size; i++) {
+    sum += arr[i];
+  }
+  return sum;
 }
 
 float array_avg(int arr[], int size) {
-    // TODO: return average as float
-    return 0.0f; // placeholder
+  int sum = array_sum(arr, size);
+  return (float)sum / size;  // cast to float for decimal average
 }

src/lab3_task2.c

@@ -1,6 +1,6 @@
 /*
  * Lab 3, Task 2
- * Student Name, Student ID
+ * Student Name: Ilham Dosdiyev, Student ID:241ADB018
  *
  * Practice using pointers as function parameters.
  * Implement:
@@ -25,22 +25,27 @@ void swap(int *x, int *y);
 void modify_value(int *x);
 
 int main(void) {
-    int a = 3, b = 7;
-    printf("Before swap: a=%d, b=%d\n", a, b);
-    swap(&a, &b);
-    printf("After swap: a=%d, b=%d\n", a, b);
+  int a = 3, b = 7;
+  printf("Before swap: a=%d, b=%d\n", a, b);
+  swap(&a, &b);
+  printf("After swap: a=%d, b=%d\n", a, b);
 
-    modify_value(&a);
-    printf("After modify_value: a=%d\n", a);
+  modify_value(&a);
+  printf("After modify_value: a=%d\n", a);
 
-    return 0;
+  return 0;
 }
 
 // Implement functions below
+
+// Swap two integers using pointers
 void swap(int *x, int *y) {
-    // TODO: swap values using a temporary variable
+  int temp = *x;  // keep the value of x in a temporary variable
+  *x = *y;        // assign the value of y to x
+  *y = temp;      // assign the original value of x to y
 }
 
+// Multiply the value by 2 using a pointer
 void modify_value(int *x) {
-    // TODO: multiply value by 2
+  *x = (*x) * 2;  // multiply the value that x points to by 2
 }