java - 为我的 java 类做一个更改程序，不知道如何循环整个程序？

Question

目前我正在开发一个程序，用户输入一个以美分为单位的值(因此 1.25 美元就是 125)，程序确定以最少的金额给出多少个硬币。我有这个工作。

令我困扰的是，我的教授希望程序不断循环，直到用户输入小于 0 的值。我不知道如何执行此操作，因为每次我尝试时，它只会循环一次而不是循环显示适当数量的硬币。

请帮忙。

这是我的代码:

import java.util.Scanner;

public class MakingChange {

    public static void main(String[] args) { 
        //Prompts user to input the change they recieved.
        Scanner sc = new Scanner(System.in);
        System.out.println("Please enter the amount of change you recieved in coin format. Example: $1.25     would be entered as 125."); 
        int Change = sc.nextInt(); //The value is then stored as an integer named Change.

        int Pennies = 0;
        int Nickels = 0;
        int Dimes = 0;
        int Quarters = 0;

        while (Change < 1){
            System.out.println("Error: Cannot enter a value less than 1!");
            //System.exit(0); //found at http://codingforums.com/java-jsp/69296-%5Bjava%5D-how-end-program.html
        }

        while (Change > 0){ //Runs a loop which determines how many of each coin is used by subtracting the values of the largest first and continuing until 0.
            if (Change >= 25){
                Change -= 25;
                Quarters++;
            }
            else if (Change >= 10){
                Change -= 10;
                Dimes++;
            }
            else if (Change >= 5){
                Change -=5;
                Dimes++;
            }
            else if (Change >= 1){
                Change -= 1;
                Pennies++;
            }


        }
        System.out.println("In total, you should have recieved:");
        System.out.printf("Number of Quarters: %3d  %n", Quarters);
        System.out.printf("Number of Dimes: %6d  %n", Dimes);
        System.out.printf("Number of Nickels: %4d  %n", Nickels);
        System.out.printf("Number of Pennies: %4d  %n", Pennies);
        //Prints out final number of coins used by type of coin.
    }

}

Answer 1

废弃你的第一个 while 循环。您不希望两个循环处理同一件事。接下来，初始化“Change”变量，但将 sc.nextInt(); 移至内部，以便每次迭代都能获取输入。最后，使循环成为 do-while 循环，以便它至少运行一次(或者您可以将更改初始化为 1)。

int Change = 0;
do{
  Change = sc.nextInt();
  // ...
}
while(Change > 0);