java - Assigning and incrementing a value during method call

Question

Can anyone explain me why such call doesn't increment my i value ?

int i = 0;
list.get(7 + (i = i++));
list.get(7 + (i = i++));

it leaves i=0 instead of increment by one at least such that in the second call it is 1.

Answer 1

i = i++就像在做：

int old_i = i; 
i = i + 1;
i = old_i; 

实际发生的是i++的值是在增量发生之前的值，然后i 将i获得...的值i。

在一行i++中将使用旧值，i然后将其递增。

Answer 2

i = i++分配第一个并增加第二个

继承人的执行本质上是这样的：

list.get(7 + (i = i)); //list.get(7);
i = i + 1; //i = 1
list.get(7 + (i = i); //list.get(8);
i = i + 1; //i = 2

++i将首先增加变量并分配第二个

Answer 3

i = i++意味着i将分配旧值i，然后将增加 1。如果你想真正增加你的值，你应该写：

int i = 0;
list.get(7 + (i++));
list.get(7 + (i++));

或者：

int i = 0;
list.get(7 + (i+1));
list.get(7 + (i+2));