计算器的开关案例声明 [英] switch-case statement for calculator

问题描述

先生！
我已经使用switch-case语句在Java中为计算器编写了代码.
但我选择了任何情况，它都会显示我在默认语句中写的消息糟糕！选择错误".
这是程序:

sir !
I have written the code in java for calculator using switch-case statement .
but i select any case it shows message "Oops! wrong choice" that i have wrote in default statement.
here''s the program:

import java.io.*;
class calculatorEx
{
public calculatorEx()
 {
      System.out.println("constructor invoked");
}
   
   public void calc()
   { 
              BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
               int a, b,c, d,ch;
               try
               {
               
               System.out.println("Enter the value of a");
               a = Integer.parseInt(br.readLine());
               System.out.println("Enter the value of b");
               b = Integer.parseInt(br.readLine());
               System.out.println("Enter the value of c ");
               c = Integer.parseInt(br.readLine());
               System.out.println("\n-----Main Menu-----\n");
               System.out.println("1.Addition");
               System.out.println("2.Multiplication");
               System.out.println("3. Subtraction");
               System.out.println("4. Average");
               
               System.out.println("------------------------------------------------------------------------");
               System.out.println("\nEnter the function which u want to perform\n");
               ch = Integer.parseInt(br.readLine());
                 switch(ch)
               {
                   case '1':
                   d = a + b + c;
                   System.out.println("The result is " + d);
                   break;
                  case '2' :
                   d = a * b * c;
                   System.out.println("The result is " + d);
                   break;
                   case '3' :
                    d = a - b - c;
                    System.out.println(" The result is" + d);
                     break;
                     case '4':
                    d = a + b + c/2;
                    System.out.println("The result is " + d);
                    break;
                    default:
                    System.out.println(" Oops! wrong choice");
                        break;
                     } 
               }
              
               
              catch(IOException ca)
               {
                   System.out.println("Exception caught" + ca);
               }
}
              

        public static void main(String ar[])
        {
            calculatorEx calc1 = new calculatorEx();
             calc1.calc();
        }
}

推荐答案

正如LanFanNinja所建议的那样，您不应尝试将Integer与char文字进行比较.尝试使用给定的代码代替开关代码.

As LanFanNinja suggested you shouldnot trying to compare an Integer to char literal. Try given code for switch block instead of your code.

switch(ch)
               {
                   case 1:
                   d = a + b + c;
                   System.out.println("The result is " + d);
                   break;
                  case 2:
                   d = a * b * c;
                   System.out.println("The result is " + d);
                   break;
                   case 3:
                    d = a - b - c;
                    System.out.println(" The result is" + d);
                     break;
                     case 4:
                    d = a + b + c/2;
                    System.out.println("The result is " + d);
                    break;
                    default:
                    System.out.println(" Oops! wrong choice");
                        break;
                     }
               }

有关更多参考:-
http://docs.oracle.com/javase/tutorial/java/nutsandbolts/switch.html [^ ]

For More reference :-
http://docs.oracle.com/javase/tutorial/java/nutsandbolts/switch.html[^]

从
更改案例语句

Change your case statements from

case '1':

到

to

case 1:

您正在尝试将整数与char文字进行比较.

you are trying to compare a integer to a char literal.

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