Question

我想用alpha beta修剪在c ++中实现tic-tac-toe。我用这个链接来帮助我。 http://www.ntu.edu.sg/home/ehchua/programming/java/JavaGame_TicTacToe_AI.html

我用c ++编写了这段代码。但这并没有运行。每次计算机轮到它时，它返回默认设置在minimax函数中的位置[-1，-1]。我无法找出bug的位置。请帮助。感谢。

#include<iostream>
using namespace std;
enum player{
    comp,user
};

void print();
char grid[3][3]={{' ',' ',' '},{' ',' ',' '},{' ',' ',' '}};
int evaluateLine(int,int,int,int,int,int);
int evaluate();
int*move();
int*minimax(int,int,int&,int&);
bool has_won();
void play(int);

int main(){
    play(user);
}
void print(){
        for(int i=0;i<3;i++){
        for(int j=0;j<3;j++)
            cout<<grid[i][j]<< "  |  ";
        cout<<"\n --   --   --  \n";
    }
}
void play(int player)
{
    int x,y;
    if(player==user){
        cout<<"Enter your move\n";
        cin>>x>>y;
        if(grid[x-1][y-1]!=' '){
            cout<<"enter a valid move\n";
            play(player);
        }
        grid[x-1][y-1]='X';
        print();
        if(has_won())
            exit(0);
        else
            play(comp);
    }
    else{
        int* x=new int[2];
        //cout<<"hi\n";
        x=move();
        cout<<x[0]<<x[1]<<endl;
        //cout<<"hi2\n";
        grid[x[0]][x[1]]='0';
        //cout<<"hi4\n";
        print();
        //cout<<"hi3\n";
        if(has_won())
            exit(0);
        else
            play(user);
    }
}
bool has_won()
{
    char win=' ';
      for (int i = 0; i <3; i++) {
         if(grid[i][0]==grid[i][1] && grid[i][1]==grid[i][2])
           {
                win=grid[i][1];
                break;
           }
         else if(grid[0][i]==grid[1][i] && grid[1][i]==grid[2][i]){
            win=grid[0][i];
            break;
         }
      }
      if(grid[1][1]==grid[0][0] && grid[1][1]==grid[2][2])
        win=grid[0][0];
      else if(grid[0][2]==grid[1][1] && grid[1][1]==grid[2][0])
        win=grid[1][1];
      if(win==' ')
       return false;
      if(win=='0'){
          cout<<"You lost\n";
          return true;
      }
      if(win=='X'){
          cout<<"You win\n";
          return true;
      }

}
int* move(){
    int *z=new int[3];
    int alpha=-100000,beta=100000;
    //cout<<alpha<<beta<<endl;

    z=minimax(4,comp,alpha,beta);
    int a[]= {z[1],z[2]};
    return a;
}
int* minimax(int level,int player,int& alpha,int& beta)
{
    int score=0;
    int row=-1,col=-1;
    if(level==0){
        score=evaluate();
    }else{
        int count=0;
        //cout<<"enter\n";
        for(int i=0;i<3;i++){
            for(int j=0;j<3;j++){
                if(grid[i][j]==' '){
                    //cout<<i<<j<<endl;
                    count++;
                    grid[i][j]=(player==0)?'0':'X';
                    score=minimax(level-1,1-player,alpha,beta)[0];
                    if(player==0){
                        if(score>alpha){
                            alpha=score;
                            row=i;
                            col=j;
                        }
                    }
                    else{
                        if(score<beta){
                            beta=score;
                            row=i;
                            col=j;
                        }
                    }
                    grid[i][j]=' ';
                    if(alpha>=beta){
                        i=3;
                        j=3;
                    }
                }
            }
        }
       if(count==0){
           score=evaluate();
        }
       else
       score=(player==0)?alpha:beta;
    }
    int a[]={score,row,col};
    return a;
}
int evaluate()
{
     int score = 0;
      // Evaluate score for each of the 8 lines (3 rows, 3 columns, 2 diagonals)
      score += evaluateLine(0, 0, 0, 1, 0, 2);  // row 0
      score += evaluateLine(1, 0, 1, 1, 1, 2);  // row 1
      score += evaluateLine(2, 0, 2, 1, 2, 2);  // row 2
      score += evaluateLine(0, 0, 1, 0, 2, 0);  // col 0
      score += evaluateLine(0, 1, 1, 1, 2, 1);  // col 1
      score += evaluateLine(0, 2, 1, 2, 2, 2);  // col 2
      score += evaluateLine(0, 0, 1, 1, 2, 2);  // diagonal
      score += evaluateLine(0, 2, 1, 1, 2, 0);  // alternate diagonal
      return score;
}
int evaluateLine(int row1,int col1,int row2,int col2,int row3,int col3)
{
     int score=0;
     if (grid[row1][col1] == '0') {
         score = 1;
      } else if (grid[row1][col1] == 'X') {
         score = -1;
      }

      // Second cell
      if (grid[row2][col2]  == '0') {
         if (score == 1) {   // cell1 is '0'
            score = 10;
         } else if (score == -1) {  // cell1 is 'X'
            return 0;
         } else {  // cell1 is empty
            score = 1;
         }
      } else if (grid[row2][col2]  == 'X') {
         if (score == -1) { // cell1 is 'X'
            score = -10;
         } else if (score == 1) { // cell1 is '0'
            return 0;
         } else {  // cell1 is empty
            score = -1;
         }
      }

      // Third cell
      if (grid[row3][col3]  == '0') {
         if (score > 0) {  // cell1 and/or cell2 is '0'
            score *= 10;
         } else if (score < 0) {  // cell1 and/or cell2 is 'X'
            return 0;
         } else {  // cell1 and cell2 are empty
            score = 1;
         }
      } else if (grid[row3][col3]  == 'X') {
         if (score < 0) {  // cell1 and/or cell2 is 'X'
            score *= 10;
         } else if (score > 1) {  // cell1 and/or cell2 is '0'
            return 0;
         } else {  // cell1 and cell2 are empty
            score = -1;
         }
      }
      return score;
}

Answer 1

问题出在你的move函数中，因为它返回一个指向局部变量的指针。当函数返回时，局部变量超出范围，并使用指向这些变量的指针导致undefined behavior。

cpp中的tic-tac-toe程序没有运行

1 个答案: