Java | PTA练习：三子棋

编写程序，实现简单的三子棋游戏。在三子棋中，双方在3×3的棋盘中轮流下棋，一方用*示，另一方用O表示。如果一方的3个棋子占据了同一行，同一列或者对角线，则该方获胜。如果棋盘已被棋子占满，但没有一方获胜则出现平局。在程序中，一方为用户，用户在界面上输入每次下棋的位置；另一方下棋的位置为随机自动生成。

import javax.swing.JOptionPane;

public class Main {

	public static void main(String[] args) {
		char []s=new char[9];
		for(int i=0;i<9;i++) {
			s[i]=(char)(i+49);
		}
		int i=0;
		while(i++<5) {
			String str=JOptionPane.showInputDialog("------------------n"
				 +"|  "+s[0]+"  |  "+s[1]+"  |  "+s[2]+"  |n"
				 +"|  "+s[3]+"  |  "+s[4]+"  |  "+s[5]+"  |n"
				 +"|  "+s[6]+"  |  "+s[7]+"  |  "+s[8]+"  |n"
				 +"------------------n"
				 + "请输入位置：");
			while(str.length()==0||(str.charAt(0)-49)<0||(str.charAt(0)-49)>8) {
				str=JOptionPane.showInputDialog("------------------n"
					 +"|  "+s[0]+"  |  "+s[1]+"  |  "+s[2]+"  |n"
					 +"|  "+s[3]+"  |  "+s[4]+"  |  "+s[5]+"  |n"
					 +"|  "+s[6]+"  |  "+s[7]+"  |  "+s[8]+"  |n"
					 +"------------------n"
					 + "输入错误，请重新输入：");
			}
			char index=str.charAt(0);
			while(s[index-49]=='*'||s[index-49]=='o') {
				str=JOptionPane.showInputDialog("------------------n"
					 +"|  "+s[0]+"  |  "+s[1]+"  |  "+s[2]+"  |n"
					 +"|  "+s[3]+"  |  "+s[4]+"  |  "+s[5]+"  |n"
					 +"|  "+s[6]+"  |  "+s[7]+"  |  "+s[8]+"  |n"
					 +"------------------n"
					 + "此位置已占用，请重新输入：");
				index=str.charAt(0);
				while(str.length()==0||(str.charAt(0)-49)<0||(str.charAt(0)-49)>8) {
					str=JOptionPane.showInputDialog("------------------n"
						 +"|  "+s[0]+"  |  "+s[1]+"  |  "+s[2]+"  |n"
						 +"|  "+s[3]+"  |  "+s[4]+"  |  "+s[5]+"  |n"
						 +"|  "+s[6]+"  |  "+s[7]+"  |  "+s[8]+"  |n"
						 +"------------------n"
						 + "输入错误，请重新输入：");
				}
			}
			s[index-49]='*';
			if((s[0]=='*'&&s[3]=='*'&&s[6]=='*')||
					   (s[1]=='*'&&s[4]=='*'&&s[7]=='*')||
					   (s[2]=='*'&&s[5]=='*'&&s[8]=='*')||
					   (s[0]=='*'&&s[1]=='*'&&s[2]=='*')||
					   (s[3]=='*'&&s[4]=='*'&&s[5]=='*')||
					   (s[6]=='*'&&s[7]=='*'&&s[8]=='*')||
					   (s[0]=='*'&&s[4]=='*'&&s[8]=='*')||
					   (s[2]=='*'&&s[4]=='*'&&s[6]=='*')) 
			{
				JOptionPane.showMessageDialog(null, "------------------n"
					 +"|  "+s[0]+"  |  "+s[1]+"  |  "+s[2]+"  |n"
					 +"|  "+s[3]+"  |  "+s[4]+"  |  "+s[5]+"  |n"
					 +"|  "+s[6]+"  |  "+s[7]+"  |  "+s[8]+"  |n"
					 +"------------------n"
					 + "恭喜你赢了");
				break;
			}
			int b=(int)(Math.random()*9);
			while(s[b]=='*'||s[b]=='o')
			{
				b=(int)(Math.random()*9);
			}
			s[b]='o';
			if((s[0]=='o'&&s[3]=='o'&&s[6]=='o')||
					   (s[1]=='o'&&s[4]=='o'&&s[7]=='o')||
					   (s[2]=='o'&&s[5]=='o'&&s[8]=='o')||
					   (s[0]=='o'&&s[1]=='o'&&s[2]=='o')||
					   (s[3]=='o'&&s[4]=='o'&&s[5]=='o')||
					   (s[6]=='o'&&s[7]=='o'&&s[8]=='o')||
					   (s[0]=='o'&&s[4]=='o'&&s[8]=='o')||
					   (s[2]=='o'&&s[4]=='o'&&s[6]=='o')) 
			{
				JOptionPane.showMessageDialog(null, "------------------n"
					 +"|  "+s[0]+"  |  "+s[1]+"  |  "+s[2]+"  |n"
					 +"|  "+s[3]+"  |  "+s[4]+"  |  "+s[5]+"  |n"
					 +"|  "+s[6]+"  |  "+s[7]+"  |  "+s[8]+"  |n"
					 +"------------------n"
					 + "失败了，再接再励");
				break;
			}

		}
		if(i==6) {
			JOptionPane.showMessageDialog(null, "------------------n"
					 +"|  "+s[0]+"  |  "+s[1]+"  |  "+s[2]+"  |n"
					 +"|  "+s[3]+"  |  "+s[4]+"  |  "+s[5]+"  |n"
					 +"|  "+s[6]+"  |  "+s[7]+"  |  "+s[8]+"  |n"
					 +"------------------n"
					 + "平局，还差一点哦");
		}
	}
}