CODE EXAMPLE FOR C

n queen problem

import java.util.*;
import java.io.*;
import java.lang.*;

class Gfg
{
    
    static final int N = 4;
    static int board[][] = { { 0, 0, 0, 0 }, 
                    { 0, 0, 0, 0 }, 
                    { 0, 0, 0, 0 }, 
                    { 0, 0, 0, 0 } };
    static void printSolution(int board[][]) 
    { 
        for (int i = 0; i < N; i++) { 
            for (int j = 0; j < N; j++) 
                System.out.print(" " + board[i][j] 
                                 + " "); 
            System.out.println(); 
        } 
    }
  
    static boolean isSafe(int row, int col) 
    { 
        int i, j; 
  
        for (i = 0; i < col; i++) 
            if (board[row][i] == 1) 
                return false; 
  
        for (i = row, j = col; i >= 0 && j >= 0; i--, j--) 
            if (board[i][j] == 1) 
                return false; 
  
        for (i = row, j = col; j >= 0 && i < N; i++, j--) 
            if (board[i][j] == 1) 
                return false; 
  
        return true; 
    } 
  
    static boolean solveRec(int col) 
    { 
        if (col == N) 
            return true; 
  
        for (int i = 0; i < N; i++) {  
            if (isSafe(i, col)) { 
                board[i][col] = 1; 
  
                if (solveRec(col + 1) == true) 
                    return true; 
  
                board[i][col] = 0; 
            } 
        }
        return false;
    }
    
    static  boolean solve() 
    { 
  
        if (solveRec(0) == false) { 
            System.out.print("Solution does not exist"); 
            return false; 
        } 
  
        printSolution(board); 
        return true; 
    }
    
    public static void main(String args[])
    {
        solve(); 
    }
}