Self Java, day02_Java increment operator: ++ decrement operators: -

Increment operator: ++ decrement operator: -

The basic meaning: make up a variable is a number 1, or have a variable drop a number 1
using the format: written before the variable name, or write after the variable name. For example: ++ num, num ++ can also
use:

•   Alone : without any other operations mixing, themselves become a separate step.
•  Mix : mixing and other operations, such as mixing with an assignment, or mixed with a printing operation, and the like.

Use difference:

•   When used alone, the front and rear ++ ++ does not make any difference. That is: ++ num; and num ++; is exactly the same.
•   In the mixing time, there are significant differences []

                 A. If it is before [++], then the variable immediately immediately [+1], and then use the results hold. [Use] the first increase after
                 B. If the [++], then the first to use the original value of the variable, and then let the variable [+1]. After the first use [plus]
        
Notes:

•     Variables can only use increment, decrement operators. Constants can not be changed, it can not be used.

demand

Since the illustration / difference operator decrementing

Code

public  class Demo06Operator {
     public  static  void main (String [] args) {
         int num1 = 10 ;
         // used alone, the front ++ 
        ++ num1; 
        System.out.println (num1); 
        // alone, after ++ 
        num1 ++ ; 
        System.out.println (num1); 
        // mixed with the printing operation time 
        int num2 = 20 is ;
         // mix, first ++ 21 immediately become variable at once, then print the results 21 
        System.out.println (+ + num2); 
        System.out.println (num2); 
        int num3 = 30 ;
         //Mixed, after ++ first variable using the original 30, and then let the resulting variable +1 31 is 
        System.out.println (num3 ++ ); 
        System.out.println (num3); 

        int Num4 = 40 ;
         // and assignment mixing, before -, then the variable immediately results to immediately -1 result1 variable 
        int result1 = - Num4; 
        System.out.println (result1); 
        System.out.println (Num4); 

        int Num5 = 50 ;
         // mixed use, after - first the original digital to result2, then I become myself again -1 new results 
        int result2 = num5-- ; 
        System.out.println (result2); 
        System.out.println (Num5 ); 

        int X = 10 ;
         int Y = 20 is ;
        // . 11 = + 20 is 31 is 
        int result3 = X + ++-y - ; 
        System.out.println (result3); 
        System.out.println (X); 
        System.out.println (Y); 

        // 30 ++ ; // error writing! ++ constants can not be used or - 
    } 
}

Results of the