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java - 改进计算器循环的建议？

问题描述

  1. 如果满足某些条件，我只想运行两个内部 do-while 循环。如果运行程序，则始终显示错误消息。如果不满足条件，您将如何更正循环以仅运行？

  2. 整个程序的 do-while 会根据字符串 Answer 重复循环。如果程序当前正在运行，则循环重复，但不允许输入 dogName。仅适用于 dogWeight。我该如何纠正？

     public static void main(String[] args) {
 System.out.println(" Welcome to Chiecoman's Dog Age Calculator");
 System.out.println();


//variables for user input
String dogName;
int dogWeight=0; 
double dogAge, humanAge =0;
Scanner keyboard = new Scanner (System.in);
String answer;

do{
// User input begins
System.out.println("Please enter your dog's name:");
dogName = keyboard.nextLine();

System.out.println("Please enter your dog's age (1-16).");
dogAge = keyboard.nextDouble();
// do-while loop to repeat until condition is met
do
 {    
 System.out.println("Error: Age is out of Range");
 System.out.println("Please enter the actual dog age (1-16)");
 dogAge= keyboard.nextDouble();    
 }        
 while (dogAge <1 || dogAge >16);

System.out.println("Please enter your dog's weight in lbs");
dogWeight = keyboard.nextInt();
// do-while loop to repeat until condition is met
do
{
 System.out.println("Error: Weight must be greater than zero");
 System.out.println("Please enter your dog's weight in lbs");
}    
while (dogWeight <1);
// how dog age is calculated
if (dogAge ==1)
humanAge=15;
else if (dogAge >=2 && dogAge <=5)
  humanAge = 4 * dogAge +15;
else if (dogAge >= 6 && dogAge <= 16 && dogWeight <20 )
  humanAge = 4 * dogAge + 16;
else if (dogAge >= 6 && dogAge <= 16 && dogWeight >= 21 &&
     dogWeight <= 50)
  humanAge = 4.5 * dogAge + 15;
else if (dogAge >= 6 && dogAge <=16 && dogWeight > 50)
  humanAge = 7.5 * dogAge;
 // displays dog age
System.out.println(dogName + "'s age in human years is " +
  humanAge);
// ask user to calculate more dog ages
System.out.println("Would you like to calculate the age of another" +
  "dog (Y/N)?");
answer = keyboard.next();
}
while (answer.equalsIgnoreCase("y"));

标签： javaloops

解决方案

请记住，在 do-while 中，第一次迭代总是发生。虽然不是代码的最佳选择 - 您可以在下面看到如何解决异常情况。

import java.util.Scanner;

public class DogAgeCalc {

    public static void main(String[] args) {
        System.out.println(" Welcome to Chiecoman's Dog Age Calculator");
        System.out.println();


//variables for user input
        String dogName;
        int dogWeight = 0;
        double dogAge, humanAge = 0;
        Scanner keyboard = new Scanner(System.in);
        String answer;

        do {
// User input begins
            System.out.println("Please enter your dog's name:");
            dogName = keyboard.nextLine();
// do-while loop to repeat until condition is met
            boolean firstAgeInput = true;
            do {
                if (!firstAgeInput) System.out.println("Error: Age is out of Range");
                System.out.println("Please enter the actual dog age (1-16)");
                dogAge = keyboard.nextInt();
                firstAgeInput = false;
            }
            while (dogAge < 1 || dogAge > 16);


// do-while loop to repeat until condition is met
            boolean firstWtInput = true;
            do {
                if (!firstWtInput) System.out.println("Error: Weight must be greater than zero");
                System.out.println("Please enter your dog's weight in lbs");
                dogWeight = keyboard.nextInt();
                firstWtInput = false;
            }
            while (dogWeight < 1);

            // how dog age is calculated
            if (dogAge == 1)
                humanAge = 15;
            else if (dogAge >= 2 && dogAge <= 5)
                humanAge = 4 * dogAge + 15;
            else if (dogAge >= 6 && dogAge <= 16 && dogWeight < 20)
                humanAge = 4 * dogAge + 16;
            else if (dogAge >= 6 && dogAge <= 16 && dogWeight >= 21 &&
                    dogWeight <= 50)
                humanAge = 4.5 * dogAge + 15;
            else if (dogAge >= 6 && dogAge <= 16 && dogWeight > 50)
                humanAge = 7.5 * dogAge;
            // displays dog age
            System.out.println(dogName + "'s age in human years is " + humanAge);
// ask user to calculate more dog ages
            System.out.println("Would you like to calculate the age of another dog (Y/N)?");
            answer = keyboard.next();
        }
        while (answer.equalsIgnoreCase("y"));
    }
}

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