什么是“<< =”运算符？(What is the “<<=” operator? [duplicate])

 
 
 这个问题在这里已有答案： 
 
 
 
  
 什么<< =运算符在Java中意味着什么？ 4个答案 
 
 
 
 
 我是Java的新学习者。 我有一个简单的使用运算符的程序，如： 
 
public class Test 

    { 
        public static void leftshift(int i, int j) 
        {
            i <<= j; 
        } 
        public static void main(String args[]) 
        {
            int i = 4, j = 2; 
            leftshift(i, j); 


       System.out.printIn(i); 
    } 
}
 
 我运行此代码，输出为4。 
 
 我知道“<< =”是左移AND赋值运算符 。 但它是如何工作的？ 

 
 
This question already has an answer here:
 
 
 
  
 What does <<= operator mean in Java?  4 answers  
 
 
 
 
I'm a new learner of Java. I have a simple program of using operator just like:
 
public class Test 

    { 
        public static void leftshift(int i, int j) 
        {
            i <<= j; 
        } 
        public static void main(String args[]) 
        {
            int i = 4, j = 2; 
            leftshift(i, j); 


       System.out.printIn(i); 
    } 
}
 
I ran this code, the output is 4.
 
I know "<<=" is a Left shift AND assignment operator. But how does it work?

原文：https://stackoverflow.com/questions/19197639