Java学习笔记13---一个循环程序的设计范例
package welcome; import java.util.Scanner; /* * 一个循环程序的设计范例 * 首先编写仅执行一次的程序(当无循环时) * 循环的设计步骤: * 1.确定程序中要重复执行的部分; * 2.加上循环模板 while(true){语句块;} * 3.重写循环控制条件,增加循环控制语句 */ public class SubtrationQuizLoop { public static void main(String[] args) { final int NUMBER_OF_QUESTIONS = 5; int correctCount = 0; String output = ""; long startTime = System.currentTimeMillis(); Scanner in = new Scanner(System.in); int count = 0; while(count < NUMBER_OF_QUESTIONS){ // 重写循环控制条件,增加循环控制语句 int number1 = (int) (Math.random() * 10); int number2 = (int) (Math.random() * 10); if (number1 < number2) { int temp = number1; number1 = number2; number2 = temp; } System.out.print(" What is " + number1 + " - " + number2 + " ? "); int answer = in.nextInt(); if (number1 - number2 == answer) { System.out.println("You are correct!"); correctCount++; } else { System.out.println( "Your answer is wrong.\n" + number1 + " - " + number2 + " should be " + (number1 - number2)); } count++; output += "\n" + number1 + "-" + number2 + "=" + answer + ((number1 - number2 == answer)? " correct" : " wrong"); } long endTime = System.currentTimeMillis(); long testTime = endTime - startTime; System.out.println("Correct count is " + correctCount + "\nTest time is " + testTime / 1000 + " seconds\n" + output); } }
运行效果:
设计过程截图:
无循环的程序版本(截图):
运行示例:
循环程序设计第二步,加循环模板
第三步,重写循环继续条件,增加循环控制语句
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