C Program to Reverse an Array Using Array Itself as a Pointer

Question: write a program in C to reverse an array containing n elements using array name itself as a pointer.

C Source Code: Reversing Array Using Array Itself Pointer

When using array name itself as a pointer, note that array name always holds the address of first element in the array. In the following program, array name arr is equivalent to &arr[0]. So array name is considered as indirect pointer.

#include<stdio.h>

int main()
{
    int arr[100],i,n, temp;

    printf("How many numbers to read? (< 100): ");
    scanf("%d", &n);

    /* Reading array using array itself as a pointer */
    printf("Enter %d numbers:\n", n);
    for(i=0;i< n;i++)
    {
        printf("arr[%d] = ", i);
        scanf("%d", (arr+i));
    }

    printf("\nOriginal array is: \n");
    for(i=0;i< n;i++)
    {
        printf(" %d\t", *(arr+i));
    }

    /* Reversing array */
    for(i=0;i< n/2;i++)
    {
        temp = *(arr + i);
        *(arr + i) = *(arr + n -1 -i);
        *(arr + n -1 -i) = temp;
    }

    /* Displaying reversed array content */
    printf("\nReversed array is: \n");
    for(i=0;i< n;i++)
    {
        printf(" %d\t", *(arr+i));
    }

    return 0;
}

Output

The output of the above program is:

How many numbers to read? (< 100): 5
Enter 5 numbers:
arr[0] = 10
arr[1] = 20
arr[2] = 30
arr[3] = 40
arr[4] = 50

Original array is:
 10      20      30      40      50
Reversed array is:
 50      40      30      20      10