java - 我将如何创建输入命令来执行代码的不同部分？ - java

Question

我创建了一个基本的java程序来确定三角形的斜边。最初，程序会要求 A 边，然后是 B 边，并自动计算斜边。

我想创建一个输入命令列表，允许用户在给出 A 侧值时键入“a”，在给出 B 侧值时键入“b”，然后键入“c”来计算斜边，或“q”退出程序。

我希望他们能够随意放入任意一侧，而不是强制用户先放入 A 面。但是，如果用户键入“c”并且 A 或 B 值缺失(或两者都缺失)，我想要一条错误消息并让用户更正它。

到目前为止我已经

import java.util.InputMismatchException;
import java.util.Scanner;


public class handleExceptions1 {
    public static void main(String[] args) {

        Scanner initial = new Scanner(System.in);
        System.out.println(" Type 'a' to enter the value for side A.\n Type 'b' to enter the value for side B.\n Type 'c' to calculate the hypotenuse.\n Or type 'q' to exit");
        String inputselected = initial.next();

        boolean repeat = true;
        double _sideA = 0;
        while (repeat) {
            try {
                Scanner input = new Scanner(System.in);
                System.out.print("Please enter side A, this may not be 0: ");
                _sideA = input.nextDouble();
                if (_sideA > 0){
                    repeat = false;
                }
            } catch (InputMismatchException e) {
                System.out.print("Error! Please enter a valid number!");
            }
        }
        boolean repeat2= true;
        double _sideB = 0;
        while (repeat2){
            try {
                Scanner input = new Scanner(System.in);
                System.out.print("Please enter side B, this may not be 0: ");
                _sideB = input.nextDouble();
                if (_sideB > 0){
                repeat2= false;
                }
            } catch (InputMismatchException e) {
                System.out.print("Error! Please enter a valid number!");
            }
        }
        double hypotenuse = Math.sqrt((_sideA*_sideA) + (_sideB*_sideB));
        System.out.print("Side C(the hypotenuse) is: "+ hypotenuse);

    }



}

我的逻辑是在“String inputselected = ...”之后放置一些内容，但我不确定是什么。如果有人可以帮助我，我将不胜感激!

Answer 1

sideA = -1;
sideB = -1;
Scanner input = new Scanner(System.in);
do
{
    System.out.println("Enter your choice ( a/b/c/q ) : ");
    char ch = in.nextChar();
    switch(ch)
    {
        case 'a': sideA = in.nextDouble();
                  if(sideA<0) 
                     System.out.println("Error! Please enter a valid number!");
                  break;
        case 'b': sideB = in.nextDouble();
                  if(sideB<0) 
                     System.out.println("Error! Please enter a valid number!");
                  break;
        case 'c': if(sideA<0 || sideB<0) 
                     System.out.println("Other two sides not yet given! please provide a and b first. ");
                  else
                     System.out.print("Side C(the hypotenuse) is: "+ Math.sqrt((_sideA*_sideA) + (_sideB*_sideB)););

                  break;
        case 'q': break;
        default : System.out.println(" Enter a valid choice! ");
    }
}while(ch!='q');