ex_5_5_2.java

java思想编程与设计模块

/*
 *文件名:ex_5_5_2.java
 *说  明:接口中使用变量
 */

import java.util.Random;

interface SharedConstants
{
	//只定义了常量的接口
	int NO = 0;
	int YES = 1;
	int MAYBE = 2;
	int LATER = 3;
	int SOON = 4;
	int NEVER = 5;
}

class Question implements SharedConstants
{
	Random rand = new Random();
	int ask() 
	{
		int prob = (int) (100 * rand.nextDouble());
		if (prob < 30)
			return NO; // 30%
		else if (prob < 60)
			return YES; // 30%
		else if (prob < 75)
			return LATER; // 15%
		else if (prob < 98)
			return SOON; // 13%
		else
			return NEVER; // 2%
	}
}
class ex_5_5_2 implements SharedConstants
{
	static void answer(int result) 
	{
		switch(result) 
		{
		case NO:
			System.out.println("No");
			break;
		case YES:
			System.out.println("Yes");
			break;
		case MAYBE:
			System.out.println("Maybe");
			break;
		case LATER:
			System.out.println("Later");
			break;
		case SOON:
			System.out.println("Soon");
			break;
		case NEVER:
			System.out.println("Never");
			break;
		}
	}
	public static void main(String args[]) 
	{
		Question q = new Question();
		answer(q.ask());
		answer(q.ask());
		answer(q.ask());
		answer(q.ask());
	}
}