c++ - Displaying Matrix elements in Strange Order -

i not sure order of printing called hence called strange.

consider following sample example:

1 3 5 2 6 7 

expected output:

1,2 1,6 1,7 3,2 3,6 3,7 5,2 5,6 5,7 

or example:

1 2 3 4 5 6 7 8 9 

output:

1,4,7 1,4,8 1,4,9 1,5,7 1,5,8 1,5,9  ... , on. 

i have analyzed number of possible combinations rows^columns given matrix.here solution:

#include <iostream> #include <vector> #include <string> #include <cstdlib> #include <cstdio>  using namespace std;  void printallpossiblecombinations(int** a, int h, int n, string prefix) {     if (h == 0)     {         (int = 0; < n; i++)         {             cout << prefix << a[0][i] << endl;         }     }     else     {         (int = 0; < n; i++)         {             string recursivestring = prefix;             recursivestring.append(to_string(a[h][i]));             recursivestring.append(1, ',');             printallpossiblecombinations(a, h-1, n, recursivestring);         }     } }  int main() {     int **a;     int m,n,k;      cout<<"enter number of rows: ";     cin>>m;     = new int*[m];      cout<<endl<<"enter number of columns: ";     cin>>n;      for(int i=0;i<m;i++)     {         a[i] = new int [n];     }      for(int i=0;i<m;i++)     {         for(int j = 0; j < n;j++)         {             cout<<"enter a[" << << "][" << j<< "] = ";             cin>>a[i][j];             cout<<endl;         }     }     printallpossiblecombinations(a, m-1, n, "");      return 0; } 

is there easy , more optimized way of doing it? please suggest.

thank you

as said, there rows^columns things physically print out in algorithm can't better o(rows^columns) algorithm , algorithm optimal you'll get.