C program to swap the contents and indexes in an array

In this article we will learn to implement a C program to swap the contents and indexes in an array. A C program is provided below for swapping the array element with the corresponding array index number.

Given an array with size n and its contents are from 0 to n-1. Swap the index and contents at that index.

i/p: a[0] = 3 a[1] = 2 a[2] = 4 a[3] = 1 a[4] = 0
o/p: a[0] = 4 a[1] = 3 a[2] = 1 a[3] = 0 a[4] = 2

The C program for above problem is as follows:

#include <stdio.h>
#include <conio.h>

int main() 
{
	int n;
	int a[20], res[20];
	printf("Enter n: ");
	scanf("%d", &n);
	printf("Enter array elements: ");
	for(int i = 0; i < n; i++)
	{
		scanf("%d", &a[i]);
	}
	for(int i = 0; i < n; i++)
	{
		res[a[i]] = i;
	}
	for(int i = 0; i < n; i++)
	{
		printf("%d ", res[i]);
	}
	getch();
    return 0;
}

Input and Output for the above program is as follows:

Enter n: 5
Enter array elements: 3 2 4 1 0
4 3 1 0 2

Suryateja Pericherla

Suryateja Pericherla, at present is a Research Scholar (full-time Ph.D.) in the Dept. of Computer Science & Systems Engineering at Andhra University, Visakhapatnam. Previously worked as an Associate Professor in the Dept. of CSE at Vishnu Institute of Technology, India.

He has 11+ years of teaching experience and is an individual researcher whose research interests are Cloud Computing, Internet of Things, Computer Security, Network Security and Blockchain.

He is a member of professional societies like IEEE, ACM, CSI and ISCA. He published several research papers which are indexed by SCIE, WoS, Scopus, Springer and others.