八皇后问题

EightOfQueen.h

#ifndef EIGHTOFQUEEN_H_INCLUDED
#define EIGHTOFQUEEN_H_INCLUDED

#include <string>
using namespace std;

class QueenChess
{
public:
    QueenChess();
    void Solve();
    string chess[8];
    int solves;
private:
    bool SafeJudge(int row,int col) const;
    void PlaceQueen(int row);
    void DrawChess() const;
};


#endif // EIGHTOFQUEEN_H_INCLUDED

EightOfQueen.cpp

#include <iostream>
#include "EightOfQueen.h"
#include <cstring>

using namespace std;

void start()
{
    QueenChess Qchess;
    Qchess.Solve();
}

//判断是否安全
bool QueenChess::SafeJudge(int row,int col) const
{
    int qrow,qcol;
    //只检查与前面的棋子是否安全
    for(qrow=0;qrow<row;qrow++)
    {
        string row_string = chess[qrow];
        qcol = row_string.find("Q");
        if(qrow == row || qcol == col || (qcol-qrow) == (col-row) || (qcol+qrow) == (row + col))
        {
            return false;
        }
    }
    return true;
}

//打印
void QueenChess::DrawChess() const
{
    cout << "\n第" << solves << "个解为："<< endl;
    cout << "   1 2 3 4 5 6 7" << endl;
    for(int i=0;i<8;i++)
    {
        cout << i << " ";
        for(int j=0;j<8;j++)
        {
            cout << chess[i][j] << " ";
        }
        cout << endl;
    }
}

//放置各列的棋子
void QueenChess::PlaceQueen(int row)
{
    for(int col=0;col<8;col++)
    {
        if(SafeJudge(row,col))      //是否安全才能放置
        {
            chess[row][col] = 'Q';
            if(row < 7)
            {
                PlaceQueen(row+1);
            }
            else
            {
                solves++;
                DrawChess();
            }
        }
        //chess[row] = "--------";
    }
}

//给出纺织成功的棋盘总数
void QueenChess::Solve()
{
    PlaceQueen(0);          //第0行开始放置
    cout << "总共解的个数：" << solves << endl;
}

//构造函数，初始化棋盘
QueenChess::QueenChess()
{
    solves = 0;
    for(int i=0;i<8;i++)
    {
        chess[i] = "--------";
    }
}

int main()
{
    start();
    return 0;
}