scratch Scratch is a program that you can download for free cs50 net and you will see in problem set 0 0 which will be posted on CS50.nettonight under problem sets in both standard and hacker editions, can you do the--can you--it will walk you through the process of getting this software.

你可以免费下载,今天晚上我会在0,放上习套题,这个习题集有两个版本，习题集可以指导你,如何下载这个软件。

哈佛公开课 - 计算机科学课程节选

It's a little more involved on a PC but it's all free, the software you can download, and Linux in similar operating systems generally come with a compiler or you run a simple command to get it.

在PC机上有点复杂，但是它是免费的，你一般下载的软件，类似Linux的操作系统等等通常都需要,一个编译器，或者你可以运行一些简单的指令来获取。

哈佛公开课 - 计算机科学课程节选