public class test {
    public static void main(String[] args) {
        int a=3;
        int b=a++;//先b=a=3,然後a++=4
        System.out.println("a="+a+ "\nb=" +b);

        System.out.println("******************");

        a=3;
        b=++a;//先a++=4,然後b=a=4
        System.out.println("a="+a+ "\nb="
 
 +b);
    }
}

a=4
b=3
******************
a=4
b=4