This is a simple 8-Queen puzzle solution written in C++

N-Queen.cpp

#include"bits/stdc++.h"
using namespace std;
main(){
int vec[]={0,1,2,3,4,5,6,7},n=8,c=0;
set <int> mset,nset;
set<int>::iterator it;

do{
mset.clear();
nset.clear();
for(int i=0;i<n;i++){
mset.insert(vec[i]+i);
nset.insert(vec[i]-i);
}
if(mset.size()==nset.size() && mset.size()==n){
printf("Solution %d\n--------\n",c++);
for (int i=0;i<n;i++){
for(int j=0;j<vec[i];j++)printf(".");
printf("Q");
for(int k=0;k<n-vec[i]+1;k++)printf(".");
puts("");
}
puts("\n--------\n");

}
}while(next_permutation(vec,vec+n));


}



/**
#equivalent Python code

from itertools import permutations
 
n = 8

def printer(vec):print ("\n".join('.' * i + 'Q' + '.' * (n-i-1) for i in vec) + "\n===\n")

cols = range(n)
for vec in permutations(cols):
    if n == len(set(vec[i]+i for i in cols)) \
         == len(set(vec[i]-i for i in cols)):
        printer( vec )
**/