Example: Pass by Reference using Pointers (Swap Example) in C

// Pass by Reference using Pointers (Swap Example)
#include <stdio.h>

// Function to swap two integers using pointers (pass by reference)
void swapByReference(int *ptrA, int *ptrB) {
    // Step 1: Declare a temporary variable to hold one of the values.
    // Use '*' to dereference ptrA, accessing the value it points to.
    int temp = *ptrA;

    // Step 2: Assign the value pointed to by ptrB to the location pointed to by ptrA.
    *ptrA = *ptrB;

    // Step 3: Assign the temporary value (original *ptrA) to the location pointed to by ptrB.
    *ptrB = temp;

    printf("Inside function: *ptrA = %d, *ptrB = %d\n", *ptrA, *ptrB);
}

int main() {
    int num1 = 10;
    int num2 = 20;

    printf("Before swapByReference: num1 = %d, num2 = %d\n", num1, num2);

    // Call swapByReference, passing the memory addresses of num1 and num2
    // The '&' operator gets the address of the variable.
    swapByReference(&num1, &num2);

    printf("After swapByReference: num1 = %d, num2 = %d\n", num1, num2);

    return 0;
}