How to shuffle a std::vector in C++

A vector shuffle can be done in the Fisher-Yates shuffle algorithm.

In this algorithm, a linear scan of a vector is done and then swap each element with a random element among all the remaining element, including the element itself.


  Declare a function show().
      Pass a constructor of a vector as a parameter within show() function.
      for (auto const& i: input)
         Print the value of variable i.
      Declare v of vector type.
         Initialize some values into v vector in array pattern.
      Declare a variable size of the integer datatype.
      Call size() function to get the size of the vector.
         Initialize size = v.size().
      for (int i = 0; i < size - 1; i++)
         int j = i + rand() % (size - i).
         call swap() function to swap the values of v[i] and v[j].
      print “Elements after getting shuffled”.
      Call show() function to display the suffled value of v vector.

Example Code

 Live Demo

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
void show(vector<int> const &input) {
   for (auto const& i: input) {
      std::cout << i << " ";
int main() {
   vector<int> v = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
   int size = v.size();
   for (int i = 0; i < size - 1; i++) {
      int j = i + rand() % (size - i);
      swap(v[i], v[j]);
   cout<<"Elements after getting shuffled"<<endl;
   return 0;


Elements after getting shuffled
2 8 5 3 1 9 4 7 6

Samual Sam
Samual Sam

Learning faster. Every day.

Updated on: 30-Jul-2019

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