C Changing Value Pointed by Pointers

#include <stdio.h>

void changeValue(int *ptr) {
    *ptr = 20;

int main() {
    int num = 10;
    int *ptr = &num;

    printf("Before change: %d\n", *ptr);


    printf("After change: %d\n", *ptr);

    return 0;

Explanation: 1. Include the necessary header file stdio.h. 2. Declare a function changeValue that takes a pointer to an integer as its argument. 3. Inside the changeValue function, dereference the pointer ptr and assign the value 20 to the integer it points to. 4. Define the main function. 5. Declare an integer variable num and set its initial value to 10. 6. Declare a pointer ptr and initialize it with the memory address of num. 7. Print the value pointed to by ptr before any changes using printf. 8. Call the changeValue function, passing the address of num (via ptr). 9. Print the value pointed to by ptr after the change made by the changeValue function. 10. Return 0, indicating successful program execution.