我想不确定如何使用开关? [英] I want to undrestan how i can use switch?

问题描述

package expnum;
import java.util.Scanner;
public class Main {

    public static void main(String[] args) {
     Scanner input = new Scanner(System.in);
     int numbers[];
     int number;
    int word;
     String expression[]={"+" , "-" , "*" , "/"};
     System.out.println("please enter 3 numbers:");
     number=input.nextInt();
     System.out.println("please enter 2 expression (+ , - ,* , /):");
      word = input.nextInt();
  //   public void answer(int expression){}
      class answer 
{
    // public static void answer (String[]args)
    {
        int expression=5;
        switch(expression)
        {
            case 1:  System.out.println(" + ");break;
            case 2:  System.out.println(" - ");break;
            case 3:  System.out.println(" * ");break;
            case 4:  System.out.println(" / ");break;
            default: System.out.println("in valid");break;
    }
}
}

     {
     }
}

是真的吗?
我想要一个给出数字和表达式(+-*/)的程序，然后给出结果.

is it true?
iwant a program that i give numbers and expression(+ - * / ) and the program give a result.
Is it useful?

推荐答案

那是您使用开关的方式，但是您所拥有的将不会做任何有用的事情你.

That is how you use a switch but what you have there isn''t going to do anything useful for you.

mf_arian写道:

mf_arian wrote:

我想要一个给出数字和表达式(+-*/)的程序，然后给出结果.

iwant a program that i give numbers and expression(+ - * / ) and the program give a result.

如果您将表达式表示为整数，那么您可以传递数字以切换您编写的代码块，但是如果您得到表达式(*，您是否会打扰您?) ，+ ...)，那么您就可以将该表达式值传递给switch块.最后是用于表达式求值的代码..?

If u getting the expression as integer then u can pass the number to switch block you have written but u if u getting expression(*,+...)then u can pass that expression value the switch block.finally where''s the code for expression evaluation..?

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