N- Queen generic solution

NQueen.cpp

#include<iostream>
using namespace std;

/** this is the size of chess board */
#define N 5

/** Given a completed board, this prints it to the stdout */
void print_solution(int state[N][N])
{
    int i,j;
    for(i=0; i<N; ++i)
    {
        for(j=0; j<N; ++j)
            cout<<state[i][j]<<" ";
        cout<<endl;
    }
    cout<<endl;
}

/** return true if placing a queen on [row][col] is acceptable
    else return false */
bool accept(int state[N][N], int row, int col)
{
    int i,j;

    /* check the column */
    for (i=0; i<N; ++i)
    {
        if (state[row][i])
            return false;
    }

    /* check the row */
    for (i=0; i<N; ++i)
    {
        if (state[i][col])
            return false;
    }

    /* check the upper left diagnol */
    for (i = row, j = col; i >= 0 && j >= 0; i--, j--)
    {
        if (state[i][j])
            return false;
    }

    /* check the lower left diagnol */
    for (i = row, j = col; i < N && j >= 0; ++i, --j)
    {
        if (state[i][j])
            return false;
    }

    /* check the upper right diagnol */
    for (i = row, j = col; i >= 0 && j < N; i--, ++j)
    {
        if (state[i][j])
            return false;
    }

    /* check the lower right diagnol */
    for (i = row, j = col; i < N && j < N; ++i, ++j)
    {
        if (state[i][j])
            return false;
    }

    /* return true if all tests passed */
    return true;
}

void solve_state(int state[N][N], int row)
{
    int i;

    /* if all queens have been placed at non conflicting positions */
    if (row == N)
    {
        print_solution(state);
        return;
    }

    /* Place queens on all positions in a given row and
       check if the state is acceptable
       Continue the process till all possibilities found */
    for(i=0; i<N; ++i)
    {
        if(accept(state, row, i))
        {
            state[row][i] = 1;
            solve_state(state, row+1);
        }
        state[row][i] = 0;
    }
}

int main()
{
    /* initialise the board */
    int state[N][N] = {0};

    solve_state (state, 0);

    return 0;
}