int one = 10 ;
        int two = 20 ;
        int three = 0 ;
        three=one+two;
    System.out.println("three=one+two=="+three);
    three+=one;
    System.out.println("three+=one=="+three);
    three-=one;

  System.out.println("three-=one=="+three);
       three*=one;
       System.out.println("three*=one=="+three);
       three/=one;
       System.out.println("three/=one=="+three);  
       three%=one;
       System.out.println("three%=one=="+three);  
      

        int one = 10 ;

        int two = 20 ;

        int three = 0 ;

        int a=one+two;

        System.out.println("three = one + two==> "+a);

        System.out.println("three += one ==> "+(a+=one));

        System.out.println("three -= one ==> "+(a-=one));

        System.out.println("three *= one ==> "+(a*=one));

        System.out.println("three /= one ==> "+(a/=one));

        System.out.println("three %= one ==> "+(a%=one));

=，把等号右边的数据赋值给等号左边的变量或常量

+=，a += b，等效于：a = (a的数据类型)(a + (b));

-=，a -= b，等效于：a = (a的数据类型)(a - (b));

=，a = b，等效于：a = (a的数据类型)(a * (b));

/=，a /= b，等效于：a = (a的数据类型)(a / (b));

%=，a %= b，等效于：a = (a的数据类型)(a % (b));