Pointers And Functions In C

Pointers And Functions In C Programming Language

With the aid of examples, you will learn about Pointers And Functions In C in this article. You will discover how to give a pointer as an argument to a function in this article. You must have a fundamental understanding of C programming’s pointers and functions in order to comprehend this notion.

Pointers may also be supplied as an argument to a function, just like any other type of argument. To better understand how this is done, let’s look at an example.

Addresses can also be sent to functions as arguments in C programming.

We can use pointers in the functional specification to accept these addresses. Pointers are used to hold addresses, which explains why. Here’s an illustration:

Example 1: Pass Addresses to Functions

#include <stdio.h>
void swap(int *n1, int *n2);

int main()
    int num1 = 5, num2 = 10;

    // address of num1 and num2 is passed
    swap( &num1, &num2);

    printf("num1 = %d\n", num1);
    printf("num2 = %d", num2);
    return 0;

void swap(int* n1, int* n2)
    int temp;
    temp = *n1;
    *n1 = *n2;
    *n2 = temp;

The output from running the program is:

num1 = 10
num2 = 5

Swap(&num1, &num2); passes the addresses of num1 and num2 to the swap() method.

These arguments are accepted by pointers n1 and n2 in the function specification.

void swap(int* n1, int* n2) {
    ... ..

Changes made to *n1 and *n2 inside the swap() method also affect num1 and num2 inside the main() function.

The swap() function swapped the values of *n1 and *n2. As a result, numbers 1 and 2 are also switched.

The return type of swap() is void, thus you can see that it doesn’t produce anything.

Example 2: Passing Pointers and Functions In C

#include <stdio.h>

void addOne(int* ptr) {
  (*ptr)++; // adding 1 to *ptr

int main()
  int* p, i = 10;
  p = &i;

  printf("%d", *p); // 11
  return 0;

In this case, the value initially saved at p, *p, is 10.

The pointer p was then provided to the addOne() method. The addOne() function provides this address to the ptr pointer.

Using (*ptr)++; inside the code, we raised the value kept at ptr by 1. Since the addresses of ptr and p pointers are identical, the value of *p inside of main() is also 11.

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