Anything where you're actually keeping track of something like a score that's having a variable that you increment -- plus, plus, or decrement, minus, minus, using the appropriate puzzle piece could certainly be compelling.

你需要保存像分数这样的事物时,你就需要一个变量,它可以自加，++，或者自减,要使用正确的拼图。

哈佛公开课 - 计算机科学课程节选

But notice unlike a for loop, if you want to declare a variable or increment or decrement to variable, you've got to do that yourself.

但请注意不像for循环，如果你想声明一个变量,或者变大或变小一个变量，你需要自己完成。

哈佛公开课 - 计算机科学课程节选