n queens

#include <iostream>
#include <cmath>
using namespace std;

bool ok(int q[], int c) {
     for(int i =0; i <c;i++){
         if(q[c]==q[i] || (c-i)==abs(q[c]-q[i]))
             return false;
}
     return true;
}

int nqueens(int n) {
   
   int* q = new int[n];
   q[0] = 0;
   int r = 0; 
   int c = 0; 
   static int solutions = 0;

   while (c >= 0){         
      c++;                    
      if(c > n){              
         solutions ++;            
         c--;
         r = q[c];           }
      else
         r = -1;

      while (c >= 0) {
         r++;
         q[c] = r;                     

         if(r > n){
            c --;
            r = q[c];       
         }

         else if(ok(q,c)){   
            break;
         }
      }
   }
        delete [] q;

        return solutions;
}

int main() {
    int n;
 cout<<"Give me a number:"<<endl;
 cin >> n;
   for (int i = 0; i < n; ++i)
      cout << "There are " << nqueens(i) << " solutions to the " << i+1 << " queens problem.\n";
   return 0;
}