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Why can't I use 'continue' inside a switch statement in Java?

开发者 https://www.devze.com 2022-12-25 04:29 出处:网络
Why is it that the following code: class swi { pub开发者_运维问答lic static void main(String[] args)

Why is it that the following code:

class swi  
{
    pub开发者_运维问答lic static void main(String[] args)  
    {  
        int a=98;
        switch(a)
        {
            default:{ System.out.println("default");continue;}
            case 'b':{ System.out.println(a); continue;}
            case 'a':{ System.out.println(a);}
        }
        System.out.println("Switch Completed");
    }
}

Gives the error:

continue outside of loop


Falling through is the standard behavior for a switch statement and so, consequently, using continue in a switch statement does not make sense. The continue statement is only used in for/while/do..while loops.

Based on my understanding of your intentions, you probably want to write:

System.out.println("default");
if ( (a == 'a') || (a == 'b') ){
    System.out.println(a);
}

I would also suggest that you place the default condition at the very end.

EDIT: It is not entirely true that continue statements cannot be used inside switch statements. A (ideally labeled) continue statement is entirely valid. For example:

public class Main {
public static void main(String[] args) {
    loop:
    for (int i=0; i<10; i++) {
        switch (i) {
        case 1:
        case 3:
        case 5:
        case 7:
        case 9:
            continue loop;
        }

        System.out.println(i);
    }
}
}

This will produce the following output: 0 2 4 6 8


The continue-Statement may be used in loops and not in switch. What you probably want is a break.


Because you have a continue outside of a loop. continue is for jumping to the next iteration of a loop, skipping the remainder of the current iteration. But you don't have any loop in that code. What you want for breaking out of a switch case block is the keyword break (see below).

There's also no need to put every case block within braces (unless you want locally-scoped variables within them).

So something a bit like this would be more standard:

class swi22
{
    public static void main(String[] args)
    {
        int a=98;
        switch(a)
        {
            default:
                System.out.println("default");
                break;
            case 'b':
                System.out.println(a);
                break;
            case 'a':
                System.out.println(a);
                break;
        }
        System.out.println("Switch Completed");
    }
}

There's also a school of thought that says the default condition should always be at the end. This is not a requirement, just a fairly widely-used convention.


Shouldn't you use break instead of continue?


continue simply moves directly to the next iteration of the loop.

break is used to break out of loops and switches.

Use break; instead of continue;

Continue:

for(x = 0; x < 10; x++)
{
   if(x == 3)
     continue;
   else       
     DoIterativeWork();       
}

Switch:

switch(a)
{
 default:{ System.out.println("default"); break;}
 case 'b':{ System.out.println(a); break;}
 case 'a':{ System.out.println(a);}
}


You are using continue where you should be using break


continue inside switch??!!! only break can be kept inside switch.!

ur code should be,

class swi22  
{
     public static void main(String[] args)  
     {  
         int a=98;
         switch(a)
         {
             default:{ System.out.println("default");break;}
             case 'b':{ System.out.println(a); break;}
             case 'a':{ System.out.println(a);}
          }
          System.out.println("Switch Completed");
     }
}
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