The description of the problem

Given a vector, you will find all of its permutations results and print them.

The codes 1

#include <bits/stdc++.h>
using namespace std;
void permutation(vector<int> &v, vector<int> &temp, vector<int> &visited);
vector<vector<int>> permutation_results;
int main()
{
    
    vector<int> visited(3, 0);
    vector<int> v;
    for (int i = 0; i < 3; i++)
    {
    
        v.push_back(i);
    }
    vector<int> temp;
    permutation(v, temp, visited);
    // cout the permutation_results
    for (int i = 0; i < permutation_results.size(); i++)
    {
    
        for (int j = 0; j < permutation_results[i].size(); j++)
        {
    
            cout << permutation_results[i][j] << " ";
        }
        cout << endl;
    }
    return 0;
}
// define a permutation of a vector
void permutation(vector<int> &v, vector<int> &temp, vector<int> &visited)
{
    
    if (temp.size() == v.size()) {
    
        permutation_results.push_back(temp);
        return;
    }
    for (auto ele : v) {
    
        if (visited[ele] == 0) {
    
            visited[ele] = 1;
            temp.push_back(ele);
            permutation(v, temp, visited);
            temp.pop_back();
            visited[ele] = 0;
        }
    }
}

$ ./test
0 1 2
0 2 1
1 0 2
1 2 0
2 0 1
2 1 0

The codes for second method (using swap)

#include <bits/stdc++.h>
using namespace std;
void permutation(vector<int> &v, vector<int> &temp, int cur);
vector<vector<int>> permutation_results;
int main()
{
    
    vector<int> visited(3, 0);
    vector<int> v;
    for (int i = 0; i < 3; i++)
    {
    
        v.push_back(i);
    }
    vector<int> temp;
    permutation(v, temp, 0);
    // cout the permutation_results
    for (int i = 0; i < permutation_results.size(); i++)
    {
    
        for (int j = 0; j < permutation_results[i].size(); j++)
        {
    
            cout << permutation_results[i][j] << " ";
        }
        cout << endl;
    }
    return 0;
}
// define a permutation of a vector
void permutation(vector<int> &v, vector<int> &temp, int cur)
{
    
    if (cur == v.size())
    {
    
        permutation_results.push_back(temp);
        return;
    }
    for (int i = cur; i < v.size(); i++)
    {
    
        swap(v[i], v[cur]);
        temp.push_back(v[cur]);
        permutation(v, temp, cur + 1);
        temp.pop_back();
        swap(v[i], v[cur]);
    }
}