Question

11.10 LAB: All permutations of names

PLEASE ANSWER IN C++!

Write a program that lists all ways people can line up for a photo (all permutations of a list of strings). The program will read a list of one word names (until -1), and use a recursive method to create and output all possible orderings of those names, one ordering per line.

When the input is:

Julia Lucas Mia -1

then the output is (must match the below ordering):

Julia Lucas Mia 
Julia Mia Lucas 
Lucas Julia Mia 
Lucas Mia Julia 
Mia Julia Lucas 
Mia Lucas Julia 

----File: main.cpp----

#include <vector>
#include <string>
#include <iostream>

using namespace std;

// TODO: Write method to create and output all permutations of the list of names.
void AllPermutations(const vector<string> &permList, const vector<string> &nameList) {

}

int main(int argc, char* argv[]) {
vector<string> nameList;
vector<string> permList;
string name;

// TODO: Read in a list of names; stop when -1 is read. Then call recursive method.

return 0;
}

Answer 1

I added another parameter to AllPermutation function -"len" which represents the swapping position.

code in text-

#include <vector>
#include <string>
#include <iostream>
#include <algorithm>
using namespace std;
// Write method to create and output all permutations of the list of names.
void AllPermutations( vector<string> &permList, vector<string> &nameList,int len) {
    //when full swapping is done
    if (len == nameList.size()-1) {
        for (int i = 0; i < nameList.size(); i++) {
            cout << nameList[i] << " ";
            permList.push_back(nameList[i]);
        }
        cout << endl;
    }
    else
    {
        // for Permutations
        for (int i = len; i <= nameList.size()-1; i++)
        {

            // Swapping
            swap(nameList[len], nameList[i]);

            // Recursion called
            AllPermutations(permList,nameList, len+1);

            //back swapping
            swap(nameList[len], nameList[i]);
        }
    }
}
int main(int argc, char* argv[]) {
vector<string> nameList;
vector<string> permList;
string name;
// Read in a list of names; stop when -1 is read. Then call recursive method.
string a="0";//for -1;
while (a!="-1"){
    cin >> a;
    if(a!="-1"){
        nameList.push_back(a);
    }
}
int len=0;//for swapping while caluclating
AllPermutations(permList,nameList,len);
return 0;
}

screen shot of code

output-

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