[英]Variable might not have been initialized in an if/else if statement
我已经发布了这段代码,但是这次还有更多的问题,变量初始化错误。 错误在第68行显示,变量为playerMove。 我一直在互联网上搜寻为什么它抱怨该变量没有初始化为无济于事。 谁能告诉我为什么我的IDE抱怨我没有为playerMove赋值?
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Rps extends JFrame
implements ActionListener
{
private final char moves[] = {'R', 'P', 'S'};
private JRadioButton rock, paper, scissors;
private JTextField display;
public Rps()
{
super("Rock, paper, Scissors");
rock = new JRadioButton(" Rock ", true);
paper = new JRadioButton(" Paper ");
scissors = new JRadioButton(" Scissors ");
ButtonGroup rpsButtons = new ButtonGroup();
rpsButtons.add(rock);
rpsButtons.add(paper);
rpsButtons.add(scissors);
JButton go = new JButton(" Go ");
go.addActionListener(this);
display = new JTextField(25);
display.setEditable(false);
display.setBackground(Color.yellow);
Container c = getContentPane();
c.setLayout(new FlowLayout());
c.add(rock);
c.add(paper);
c.add(scissors);
c.add(go);
c.add(display);
}
/**
* returns -1 if the player wins,
* 0 if it's a tie, and 1 if the computer wins
*/
private int nextPlay(char computerMove, char playerMove)
{
if ((computerMove == 'R'&&playerMove == 'S')||(computerMove == 'S'&&playerMove=='P')||(computerMove=='P'&&playerMove=='R')){
return 1;}
else if ((computerMove == 'R'&&playerMove == 'R')|| (computerMove=='S'&&playerMove=='S')||(computerMove=='P'&&playerMove=='P')){
return 0;}
return -1;
}
public void actionPerformed(ActionEvent e)
{
char playerMove, computerMove; //Errors start around here
if (rock.isSelected()){
playerMove = 'R';}
else if (paper.isSelected()){
playerMove = 'P';}
else if (scissors.isSelected()){
playerMove = 'S';}
int k = (int)(Math.random() * 3);
computerMove = moves[k];
int result = nextPlay(computerMove, playerMove); //More errors
String msg = " You said " + makeWord(playerMove) + ", I said " +
makeWord(computerMove); //Even more errors
if (result < 0)
msg += " -- you win.";
else if (result == 0)
msg += " -- tie.";
else if (result > 0)
msg += " -- I win.";
display.setText(msg);
}
private String makeWord(char move)
{
String word = "";
switch (move)
{
case 'R': word = "ROCK"; break;
case 'P': word = "PAPER"; break;
case 'S': word = "SCISSORS"; break;
}
return word;
}
public static void main(String[] args)
{
Rps window = new Rps();
window.setBounds(300, 300, 300, 140);
window.setDefaultCloseOperation(EXIT_ON_CLOSE);
window.setVisible(true);
}
}
您已经声明了playerMove
,但是在下面
char playerMove, computerMove; //Errors start around here
if (rock.isSelected()){
playerMove = 'R';
} else if (paper.isSelected()){
playerMove = 'P';
} else if (scissors.isSelected()){
playerMove = 'S';
} // add an else with default value or initialize it in its declaration above
如果所有if
条件都不为true
,会发生什么? 您的变量将保持未初始化状态。 编译器不允许这样做。 将else
块添加到if-else
或立即使用一些默认值对其进行初始化
char playerMove = '0';
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