And this puzzle piece here colored in blue because it's a Boolean expression is just something that--whose answer is either a yes or no, 0 true or false, one or zero.

这个拼图染成蓝色,因为它是布尔表达式,它的结果只可能是肯定或否定，对或错，1或者。

哈佛公开课 - 计算机科学课程节选

- Well -- and I'll fix this blue next time -- I'm first telling the compiler I need access to the standard io library because printf is declared there.

哦！--下次我把这个字体颜色改成蓝色的-,我先告诉编译器--我需要使用,标准输入输出库,因为printf在那个库里面申明的。

哈佛公开课 - 计算机科学课程节选