reverse() in C++ STL

Last Updated : 27 Sep, 2025

In C++, the reverse() is a built-in function used to reverse the order of elements in the given range of elements. This range can be any STL container like vector or can be an array.

C++

#include <bits/stdc++.h>
using namespace std;

int main() {
    vector<int> v = {1, 2, 3, 4, 5};

    // Reversing the vector
    reverse(v.begin(), v.end());

    for (int i : v) cout << i << " ";
    return 0;
}

Output

5 4 3 2 1

Syntax of reverse()

The reverse() function is defined in the <algorithm> header file.

reverse(first, last);

Parameters:

first: Iterator to the first element in the range.
last: Iterator to the theoretical element just after the last element in the range.

Return Value:

This function does not return any value. It reverses the range in-place.

Examples

Reversing an Array

The below examples show how to use the reverse() function to reverse variety of data containers.

C++

#include <bits/stdc++.h>
using namespace std;

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int n = sizeof(arr) / sizeof(arr[0]);

  	// Reverse the array arr
    reverse(arr, arr + n);

    for (int i : arr) cout << i << " ";
    return 0;
}

Output

5 4 3 2 1

Reverse a String

C++

#include <bits/stdc++.h>
using namespace std;

int main() {
    string s = "abcd";

  	// Reverse the string s
    reverse(s.begin(), s.end());

    cout << s;
    return 0;
}

Output

dcba

Left Rotate a Vector using reverse()

The left rotation of a vector can be done by using reverse() three times on it.

C++

#include <bits/stdc++.h>
using namespace std;

int main() {
    vector<int> v = {1, 3, 6, 2, 9};
    int n = v.size();
    int d = 2;

    // Left rotate the vector by d place
    reverse(v.begin(), v.begin() + d);
    reverse(v.begin() + d, v.end());
    reverse(v.begin(), v.end());

    for (auto i : v)
        cout << i << " ";
    return 0;
}

Output

6 2 9 1 3

reverse() in C++ STL

H

Hardik Gaur

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