Program : Reverse the Elements of an Array Without Additional Memory in C++

Solution :

Sometime, you see this problem as “Reverse the elements of an array in-place”. Here, “in-place” means that the original array is modified directly, without using additional arrays or data structures.

#include <iostream>
using namespace std;

int main() {
    const int size = 5; // Change the size to fit your array
    int arr[size],i;
    int start = 0, end = size - 1,temp;

    cout << "Enter " << size << " elements of an array : ";
    for (i = 0; i < size; i++) {
        cin >> arr[i];
    }

    while (start < end) {
        temp = arr[start];
        arr[start] = arr[end];
        arr[end] = temp;
        start++; // Move start index towards the center
        end--;   // Move end index towards the center
    }

    cout << "Reversed array: ";
    for (int i = 0; i < size; i++) {
        cout << arr[i] << " ";
    }
    return 0;
}

Output

Enter 5 elements of an array: 
10 
12 
33 
4 
35 
Reversed array : 35 4 33 12 10

Dry Run :

So, from the above table, final value of array is 35 4 33 12 10.

Want to practice more problems involving Array 1-D ? Click here.