JAVA Switch statement

/*

Switch statement

switch (expression) {

Case value 1:

Statement body 1;

Break

Case Value 2:

Statement body 2;

Break

..

..

Default

Statement body n+1;

Break

}

Format interpretation of B:switch statements

(1): switch indicates that this is a switch statement

Value of expression: Byte,short,int,char

JDK5 can be enumerated later (what is an enumeration, again later)

JDK7 can be a string later

(2): The case is followed by the value to be compared with the expression

(3): The statement body part can be one or more statements

(4): Break indicates interrupt, end of meaning, can end switch statement

(5):d The Efault statement indicates that all cases do not match, the contents of that place are executed, and the else of the IF statement is similar

C: Face question

Can byte be used as a switch expression? OK

Can long be used as a switch expression? No

Can string be used as an expression of switch? Yes, after the JDK7.

D: Execution Process:

The value of an expression is evaluated first:

Match the value in the case.

If a successful match succeeds, the statement that matches the value below is encountered when the break jumps out, otherwise the default control is executed

A: Integers (two-digit plus-minus multiplier)

There are two integers

Keyboard entry gets two integers

I have a word for you to choose from.

1: Perform an addition of two numbers

2: Perform a subtraction of two numbers

3: Perform a multiplication of two numbers

4: Perform a division of two numbers

*/

Guide Package

Import Java.util.scanner;class switchdemo{public static void Main (string[] args) {//create object Scanner sc = new Scanner (system.i n); System.out.println ("Please enter the first integer!"); int x = Sc.nextint (); System.out.println ("Please enter a second integer!");        int y = Sc.nextint (); SYSTEM.OUT.PRINTLN ("Please select the action you want to do:!");        System.out.println ("1: Addition 2: Subtraction 3: Multiplication 4: Division"); int choose = Sc.nextint (); switch (choose) {case 1:system.out.println ("sum of two numbers is:" + (x+y)); Break Case 2:system.out.println ("The difference between two numbers is:" + (x-y)); Break Case 3:SYSTEM.OUT.PRINTLN ("the product of two numbers is:" + (x*y)); Break Case 4:system.out.println ("quotient of two numbers is:" + (x/y)); Break DEFAULT:SYSTEM.OUT.PRINTLN ("Not supported for the time being, I will give you support!!"); }}}

/*

Switch statement considerations

A:case can only be constants, cannot be variables, and values after multiple case cannot appear the same

Can B:default be omitted?

It can be omitted, but it is not recommended, because it is used to prompt for incorrect conditions.

Can c:break be omitted? The program runs out of a break and does not encounter a break down execution until a break is encountered or the program finishes executing

can be omitted, but the result may not be what we want.

There is a phenomenon: case penetrating.

In the end, we recommend not omitting

D:default must be at the end?

No, it can be anywhere. But the suggestion at the end.

Because the program execution process is a case-by-case judgment case all values do not match to execute the statement in default

The end condition of the E:switch statement

A: It's over when you hit the break.

B: Execution ends at the end.

*/

Guide Package

Import java.util.scanner;class switchnoticedemo{public static void main (String[]  args)  {//Create Object Scanner sc = new scanner (system.in); System.out.println ("Please enter the first integer!"); Int x = sc.nextint (); System.out.println ("Please enter a second integer!"); Int y = sc.nextint ();         system.out.println (" Please select the action you want to do:! "); System.out.println ("1: addition   2: Subtraction  3: Multiplication  4: Division");         int choose = sc.nextint ();         //int a  = 2;switch (choose) {     case 1:system.out.println ("sum of two numbers is:" + (x+y));  break;/*  case a://  requires constant expression System.out.println ("the difference between two numbers is:" + (x-y)); break;   case 2://case  Label Repeat System.out.println ("Two number of JKHJKL is:" + (x-y));  break;   */  case 2:system.out.println ("The difference between two numbers is:" + (x-y));  break;       CASE 3:SYSTEM.OUT.PRINTLN ("The product of two numbers is:" + (X*y));  break; case  4:system.out.println ("Two number of the quotient is:" + (x/y));  break;default:system.out.println ("Not supported for the time being, give you support!!!");   }}}

This article from the "Clear Sky" blog, declined reprint!

JAVA Switch statement