How to reverse a Vector using STL in C++?

November 10, 2020   C++ Programming , STL

Problem Statement:

Given a vector, obtain the reverse of a vector using STL in C++.

Example

Input: {19, 35, 55, 121, 56, 42}
result : {42,56,121,55,35,19}

Input: {13, 74, 25, 49, 26, 2}
result : {2,26,49,25,74,13}

READ ABOUT ARE VECTORS

How to solve it:

 Reversing can be achieved with the assistant of reverse() function implemented in STL algorithm library.

Syntax:

std::reverse(start_index, last_index);
it will reverse the original vector.

Implementation:

#include <iostream>
#include<vector> 
#include<algorithm>
int main() 
{ 
    // Intialize the vector
    std :: vector<int> a = {19, 35, 55, 121, 56, 42}; 
   // reversing the vector
   std::reverse(a.begin(),a.end());
  // prining the reversed array
  for(int i=0;i<a.size();i++){
  std::<<a.at(i);
  }
    return 0; 
} 

Output:

42 56 121 55 35 19