变量这段代码是胡扯游戏(java的Deitel公司如何编程)声明和初始化在java中
为什么myPoint变量需要初始化,如果没有会发生编译错误???
我的意思是如果有赢或第一卷损失有没有需要初始化mypoint(因为它没有被使用了)
而且如果在第一卷没有输赢,myPoint得值在开关默认标签
import java.util.Random;
public class Craps
{
// create random number generator for use in method rollDice
private static final Random randomNumbers = new Random();
// enumeration with constants that represent the game status
private enum Status { CONTINUE, WON, LOST };
// constants that represent common rolls of the dice
private static final int SNAKE_EYES = 2;
private static final int TREY = 3;
private static final int SEVEN = 7;
private static final int YO_LEVEN = 11;
private static final int BOX_CARS = 12;
// plays one game of craps
public static void main(String[] args)
{
int myPoint = 0; // point if no win or loss on first roll
Status gameStatus; // can contain CONTINUE, WON or LOST
int sumOfDice = rollDice(); // first roll of the dice
// determine game status and point based on first roll
switch (sumOfDice)
{
case SEVEN: // win with 7 on first roll
case YO_LEVEN: // win with 11 on first roll
gameStatus = Status.WON;
break;
case SNAKE_EYES: // lose with 2 on first roll
case TREY: // lose with 3 on first roll
case BOX_CARS: // lose with 12 on first roll
gameStatus = Status.LOST;
break;
default: // did not win or lose, so remember point
gameStatus = Status.CONTINUE; // game is not over
myPoint = sumOfDice; // remember the point
System.out.printf("Point is %d\n", myPoint);
break; // optional at end of switch
} // end switch
// while game is not complete
while (gameStatus == Status.CONTINUE) // not WON or LOST
{
sumOfDice = rollDice(); // roll dice again
// determine game status
if (sumOfDice == myPoint) // win by making point
gameStatus = Status.WON;
else
if (sumOfDice == SEVEN) // lose by rolling 7 before point
gameStatus = Status.LOST;
} // end while
// display won or lost message
if (gameStatus == Status.WON)
System.out.println("Player wins");
else
System.out.println("Player loses");
} // end main
// roll dice, calculate sum and display results
public static int rollDice()
{
// pick random die values
int die1 = 1 + randomNumbers.nextInt(6); // first die roll
int die2 = 1 + randomNumbers.nextInt(6); // second die roll
int sum = die1 + die2; // sum of die values
// display results of this roll
System.out.printf("Player rolled %d + %d = %d\n",
die1, die2, sum);
return sum; // return sum of dice
} // end method rollDice
} // end class Craps
这在任何Java教程中都有介绍。 –