suduku solver

#include <bits/stdc++.h> 
using namespace std; 
#define UNASSIGNED 0 
#define N 9 

bool FindEmptyLocation(int grid[N][N], int &row, int &col); 
bool isSafe(int grid[N][N], int row, int col, int num); 

bool SolveSudoku(int grid[N][N]) 
{ 
	int row, col; 

	if (!FindEmptyLocation(grid, row, col)) 
	return true; 

	for (int num = 1; num <= 9; num++) 
	{ 
		if (isSafe(grid, row, col, num)) 
		{ 

			grid[row][col] = num; 

			if (SolveSudoku(grid)) 
				return true; 

			grid[row][col] = UNASSIGNED; 
		} 
	} 
	return false; 
} 

bool FindEmptyLocation