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Pass by reference in C

Pass by Reference

Pass by reference in C refers to passing the memory address (i.e., reference) of a variable to a function instead of the value.
This allows the function to modify the original variable in memory, rather than just working with a copy of the value.
In C, pass by reference is implemented using pointers. A pointer to a variable is passed to the function, which can then modify the value of the variable by dereferencing the pointer.

Example

Program below demonstrates pass by reference in C:

#include <stdio.h>

// Function that takes a pointer to an int
void increment(int *num)
{
    (*num)++; // dereference the pointer and increment the value
}

int main()
{
    int num = 0;

    printf("num = %d\n", num); // prints "num = 0"

    increment(&num); // pass a pointer to the "num" variable

    printf("num = %d\n", num); // prints "num = 1"

    return 0;
}

Output:

Explanation

The increment function takes a pointer to an int as an argument.
Inside the function, the pointer is dereferenced using the * operator, and the value of the variable is incremented.
When increment(&num) is called in the main function, a pointer to the num variable is passed as an argument.
The increment function then modifies the value of the num variable in memory, and the updated value is printed in the main function.

Pass by Reference
Example