Pointers in C

#include <stdio.h>

int main() {
    int num = 42;

    // & = address-of operator — variable चा address देतो
    printf("Value: %d\n", num);
    printf("Address: %p\n", &num);   // ex: 0x7fff5a2b

    // Pointer declare करणे — * वापरतात
    int *ptr = &num;   // ptr मध्ये num चा address आहे

    printf("ptr holds: %p\n", ptr);    // num चा address
    printf("*ptr = %d\n", *ptr);       // 42 — dereference

    // Pointer द्वारे value बदलणे
    *ptr = 100;
    printf("num is now: %d\n", num);   // 100 — बदलला!

    return 0;
}

#include <stdio.h>

int main() {
    int arr[] = {10, 20, 30, 40, 50};
    int *ptr = arr;   // arr हे arr[0] चा address आहे

    // Pointer arithmetic
    printf("%d\n", *ptr);       // 10 — arr[0]
    printf("%d\n", *(ptr+1));   // 20 — arr[1]
    printf("%d\n", *(ptr+2));   // 30 — arr[2]

    // Pointer वापरून array traverse करणे
    for (int i = 0; i < 5; i++) {
        printf("%d ", *(ptr + i));
    }
    // Output: 10 20 30 40 50

    return 0;
}

#include <stdio.h>

// Pointer receive करतो — original बदलू शकतो
void doubleIt(int *x) {
    *x = *x * 2;
}

void swap(int *a, int *b) {
    int temp = *a;
    *a = *b;
    *b = temp;
}

int main() {
    int num = 5;
    doubleIt(&num);
    printf("num after double: %d\n", num);  // 10

    int x = 3, y = 7;
    swap(&x, &y);
    printf("After swap: x=%d, y=%d\n", x, y);  // x=7, y=3

    return 0;
}