Lab2 work

src/hello.c

@@ -1,12 +1,10 @@
 
 #include <stdio.h>
-
 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 Hazal!\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]);
   }
   return 0;
-}
+}

src/lab2_1.c

@@ -1,28 +1,22 @@
 #include <stdio.h>
 
-/*
-    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_to_n(int n){
+    int s = 0;
+    for(int i = 1; i <= n; i++){
+        s += i;
+    }
+    return s;
 }
 
-int main(void) {
+int main(void){
     int n;
-
     printf("Enter a positive integer n: ");
-    scanf("%d", &n);
-
-    // TODO: validate input, call function, and print result
+    if (scanf("%d", &n) != 1) return 0;
 
+    if(n < 1){
+        printf("Error: n must be >= 1\n");
+    } else {
+        printf("Sum 1..%d = %d\n", n, sum_to_n(n));
+    }
     return 0;
 }

src/lab2_2.c

@@ -1,28 +1,22 @@
 #include <stdio.h>
 
-/*
-    Task:
-    Write a function `long long factorial(int n)` that computes n!
-    using a loop (not recursion).
-
-    In main():
-      - Ask user for an integer n
-      - If n is negative, print an error and exit
-      - Otherwise, call factorial and print the result
-*/
-
-long long factorial(int n) {
-    // TODO: compute factorial iteratively
-    return 1; // placeholder
+long long factorial(int n){
+    long long r = 1;
+    for(int i = 1; i <= n; i++){
+        r *= i;
+    }
+    return r;
 }
 
-int main(void) {
+int main(void){
     int n;
+    printf("Enter n: ");
+    if (scanf("%d", &n) != 1) return 0;
 
-    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 {
+        printf("%d! = %lld\n", n, factorial(n));
+    }
     return 0;
 }

src/lab2_3.c

@@ -1,28 +1,26 @@
 #include <stdio.h>
 
-/*
-    Task:
-    Write a function `int is_prime(int n)` that returns 1 if n is prime,
-    0 otherwise.
-
-    In main():
-      - Ask user for an integer n (>= 2)
-      - If invalid, print an error
-      - Otherwise, print all prime numbers up to n
-*/
-
-int is_prime(int n) {
-    // TODO: check if n is prime using loop up to sqrt(n)
-    return 0; // placeholder
+int is_prime(int n){
+    if(n < 2) return 0;
+    for(int i = 2; i*i <= n; i++){
+        if(n % i == 0) return 0;
+    }
+    return 1;
 }
 
-int main(void) {
+int main(void){
     int n;
+    printf("Enter n: ");
+    if (scanf("%d", &n) != 1) return 0;
 
-    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");
+    } else {
+        printf("Primes up to %d:\n", n);
+        for(int i = 2; i <= n; i++){
+            if(is_prime(i)) printf("%d ", i);
+        }
+        printf("\n");
+    }
     return 0;
 }