find permutations

1void permute(string a, int l, int r)  
2{  
3    // Base case  
4    if (l == r)  
5        cout<<a<<endl;  
6    else
7    {  
8        // Permutations made  
9        for (int i = l; i <= r; i++)  
10        {  
11  
12            // Swapping done  
13            swap(a[l], a[i]);  
14  
15            // Recursion called  
16            permute(a, l+1, r);  
17  
18            //backtrack  
19            swap(a[l], a[i]);  
20        }  
21    }  
22}  

1void find_permutations(vector<int> &array, size_t index, vector<int> current_perm, vector<vector<int>> &res){
2    if(index == array.size()) 
3        res.push_back(current_perm);
4    else{
5        for(size_t i = 0; i <= current_perm.size(); ++i){
6            vector<int> new_perm(current_perm.begin(), current_perm.end());
7            new_perm.insert(new_perm.begin()+i, array[index]);
8            find_permutations(array, index+1, new_perm, res);
9        }
10    }
11}

1ABC
2ACB
3BAC
4BCA
5CBA
6CAB