Switch-case statements in Java

The Switch-case statement in Process Control has always been a weakness of mine.

Whenever the exam or interview written test, always confused, I think this should be my foundation is too poor reason!

In order to completely solve this problem, we have to spend a little effort!

First of all, explain the problem from the principle:

switch (expression)

{Case constant Expression 1: statement 1;

....

Case constant Expression 2: statement 2;

Default: statement; }

1.default is to execute it without a match, and default is not necessary.

The statement after 2.case can be without curly braces.

The judgment condition of the 3.switch statement can accept Int,byte,char,short and cannot accept other types.

4. Once the case is matched, the following program code is executed sequentially, regardless of whether the subsequent case matches, until the break is met, which allows several case execution to execute the unified statement.

Principle, the following is a few confusing examples.

1. Standard type (there are break statements behind case)

int i=3;
switch(i)
{
case 1:
System.out.println(1);
break;
case 2:
System.out.println(2);
break;
case 3:
System.out.println(3);
break;
default:
System.out.println("default");
break;
}

Output results:

3