Reverse an Array In-Place

Solution With Approach by Abhilash

#include <stdio.h>

void reverse_array(int arr[], int n) {
    // Your logic here
    int start=0, end = n-1, temp;
    while(start<=end){
        temp = arr[start];
        arr[start] = arr[end];
        arr[end]= temp;
        start++;
        end--;
    }

}

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

1. Initialise variables, start and end indicators

              int start=0, end = n-1, temp;

      2. Set the Looping condition. For even number of elements in the array, (start<end) for           odd (start=end). Now combine together, since we dont know if the input array will               have even number of elements or odd.

          while(start<=end)

      3. Assign the first element to a temporary variable - temp, then the now first element              value is replaced by last value.(arr[end]). Then assign the last element with temp. 

    while(start<=end){
        temp = arr[start];
        arr[start] = arr[end];
        arr[end]= temp;
        start++;
        end--;
    }           

      4. Finally Increment the start, and decrement the end flags.