Reverse an Array In-Place

Code

#include <stdio.h>

void reverse_array(int arr[], int n) {
    for ( int i = 0, j = n - 1; i < j; i++,j--){
            int temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
    }

int main() {
    int n;
    scanf("%d", &n);

    int arr[100];
    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    reverse_array(arr, n);

    for (int i = 0; i < n; i++) {
        printf("%d", arr[i]);
        if(i < n-1){
        	printf(" ");
        }
    }
    return 0;
}

Solving Approach

• Use two pointers — i at start and j at end of the array.
• Swap elements at i and j.
• Move i forward and j backward each time.
• Repeat until i ≥ j (array is reversed).
• Print the reversed array.