javascript x++ 和 ++x 有什么区别
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What is the difference between x++ and ++x
提问by steve
Possible Duplicate:
Incrementing in C++ - When to use x++ or ++x?
What is the difference between x++ and ++x ?
x++ 和 ++x 有什么区别？
回答by Justin Niessner
x++executes the statement and then increments the value.
x++执行语句，然后增加值。
++xincrements the value and then executes the statement.
++x增加值，然后执行语句。
var x = 1;
var y = x++; // y = 1, x = 2
var z = ++x; // z = 3, x = 3
回答by Ben Lee
++xis higher in the order of operations than x++. ++xhappens prior to assignments, but x++happens after assignments.
++x操作顺序高于x++。++x发生在赋值之前，但x++发生在赋值之后。
For exmaple:
例如：
var x = 5;
var a = x++;
// now a == 5, x == 6
And:
和：
var x = 5;
var a = ++x;
// now a == 6, x == 6
回答by Rocket Hazmat
x++returns x, then increments it.
x++返回 x，然后增加它。
++xincrements x, then returns it.
++x增加 x，然后返回它。
回答by SLaks
If you write y = ++x, the yvariable will be assigned after incrementing x.
If you write y = x++, the yvariable will be assigned beforeincrementing x.
如果你写y = ++x，y变量将在递增后分配x。
如果你写y = x++，y变量将在递增之前被赋值x。
If xis 1, the first one will set yto 2; the second will set yto 1.
如果x是1，第一个将设置y为2；第二个将设置y为1。
