C Program to Reverse an Array

An array is a group of related items that store with a common name.

Syntax

The syntax is as follows for declaring an array −

datatype array_name [size];

Initialization

An array can also be initialized at the time of declaration −

int a[5] = { 10,20,30,40,50};

Reversing array in C

We can reverse array by using swapping technique.

For example, if 'P' is an array of integers with four elements −

P[0] = 1, P[1] = 2, P[2] = 3 and P[3]=4

Then, after reversing −

P[0] = 4, P[1] = 3, P[2] = 2 and P[3]=1

Example

Following is the C program to reverse an array −

#include <stdio.h>
int main(){
   int num, i, j, array1[50], array2[50];
   printf("Enter no of elements in array
");
   scanf("%d", &num);
   printf("Enter array elements
");
   for (i = 0; i < num ; i++)
      scanf("%d", &array1[i]);
   // Copying elements into array
   for (i = num - 1, j = 0; i >= 0; i--,j++)
      array2[j] = array1[i];
   // Copying reversed array into the original
   for (i = 0; i < num; i++)
      array1[i] = array2[i];
   printf("The reversed array:
");
   for (i = 0; i< num; i++)
      printf("%d
", array1[i]);
   return 0;
}

Output

Upon execution, you will receive the following output −

Enter no of elements in array
4
Enter array elements
20
50
60
70
The reversed array:
70
60
50
20