#include <iostream>
using namespace std;
int tablet[20][20]={0};

int five(){
	for (int i=0;i<20;i++){
		for (int j=0;j<20;j++){
			if((tablet[i][j]==1&&tablet[i+1][j]==1&&tablet[i+2][j]==1&&tablet[i+3][j]==1&&tablet[i+4][j]==1)||\
			(tablet[i][j+1]==1&&tablet[i][j+2]==1&&tablet[i][j+3]==1&&tablet[i][j+4]==1&&tablet[i][j]==1)||\
			(tablet[i+4][j+4]==1&&tablet[i+3][j+3]==1&&tablet[i+2][j+2]==1&&tablet[i+1][j+1]==1&&tablet[i][j]==1)){
				return 1;
			}else if((tablet[i][j]==2&&tablet[i+1][j]==2&&tablet[i+2][j]==2&&tablet[i+3][j]==2&&tablet[i+4][j]==2)||\
			(tablet[i][j+1]==2&&tablet[i][j+2]==2&&tablet[i][j+3]==2&&tablet[i][j+4]==2&&tablet[i][j]==2)||\
			(tablet[i+4][j+4]==2&&tablet[i+3][j+3]==2&&tablet[i+2][j+2]==2&&tablet[i+1][j+1]==2&&tablet[i][j]==2)){
				return 2;
			}else{
				return 0;
			}
		}
	}
}
void out(){
	for (int i=0;i<20;i++){
		for (int j=0;j<20;j++){
			cout<<tablet[j][i]<<" ";
		}
		cout<<endl;
	}
}



int main() {
	cout<<"Welcome to gobang, rules: each time it is your turn to play chess, enter two \
	integers x and y (a space in between) to represent x and y coordinates, 0 0 in the upper\
	 left corner and 19 19 in the lower right corner. In the chessboard, black is 1, white\
	  is 2, and empty is 0."<<endl; 
	int a=0;
	while (1){
		int x,y;
		if (a%2==0){
			cout<<"black's turn."<<endl;
			cin>>x>>y;
			if (x<20&&y<20&&tablet[y][x]==0){
				tablet[y][x]=1;
			}else{
				cout<<"Maybe it's out of bounds and it's overwriting another piece. Please retype"<<endl;
				continue;
			}
		}else{
			cout<<"white's turn."<<endl;
			cin>>x>>y;
			if (x<20&&y<20&&tablet[y][x]==0){
				tablet[y][x]=2;
			}else{
				cout<<"Maybe it's out of bounds and it's overwriting another piece. Please retype"<<endl;
				continue;
			}
		}
		a++;
		out();
		int five_=five();
		if (five_!=0){
			break;
		} 
	}
	if (five()==1){
		cout<<"black wins!!!";
	}else{
		cout<<"white wins!!!";
	}
	return 0;
}

为什么这个五子棋代码会错误？（连成5个了但是并不会结束，（主要问题大概也许是在five()函数里面对吧））