java - Java 后递增器的行为

Question

    public static void main(String[] args) {
    int a = 1;
    int b = a++;

    System.out.println(b);
}

为什么上面的代码打印1？有人告诉我 a++ 意味着你会得到 a 的值。然后增加它。但上面的代码从未增加 a 并只是打印 1。有人可以解释一下这里发生了什么吗？

Answer 1

它按预期工作；代码解释如下:

public static void main(String[] args) {
    // a is assigned the value 1
    int a = 1;
    // b is assigned the value of a (1) and THEN a is incremented.
    // b is now 1 and a is 2.
    int b = a++;

    System.out.println(b);
    // if you had printed a here it would have been 2
}

这是相同的代码，但预先递增了 a:

public static void main(String[] args) {
    // a is assigned the value 1
    int a = 1;
    // a is incremented (now 2) and THEN b is assigned the value of a (2) 
    // b is now 2 and so is a.
    int b = ++a;

    System.out.println(b);
    // if you had printed a here it would have been 2 so is b.
}