Introduction to the Programming Environment

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来自 Duke University 的课程

Writing, Running, and Fixing Code in C

63 个评分

Duke University

Writing, Running, and Fixing Code in C

63 个评分

课程 2（共 4 门，Specialization Introduction to Programming in C）

Building on the course Programming Fundamentals, this course will teach you how to write code by first planning what your program should do—an important approach for novice and professional programmers. You will learn how to compile and run your program, and then how to test and debug it. This course builds on the Seven Steps you have already learned and provides a framework for systematically testing for problems and fixing them, so you can find and fix problems efficiently.

从本节课中

Writing Code

In this module, you will learn to write code and do your first assignment in the Practice Programming Environment. You have practiced the first four steps of the Seven Steps in the previous course, and you will review them here before learning Step 5: Translating Your Algorithm to Code. Expert programmers spend most of their time planning before they begin writing code, and you will learn to do the same!

Introduction to the Programming Environment6:02

Editing Files with Emacs8:08

More about Git4:29

与讲师见面

Andrew D. Hilton
Associate Professor of the Practice
Electrical and Computer Engineering
Genevieve M. Lipp
Adjunct Professor
Electrical and Computer Engineering/Mechanical Engineering
Anne Bracy
Senior Lecturer
Computer Science, Cornell University

Okay, now you're ready to start actually writing some code in a Unix environment.

We're going to take a little bit of time to introduce you to how to use this environment,

how to edit files,

how to use Git and various other tools that you'd be using as your program.

So here I am in Coursera on the first assignment,

which is really just a walkthrough of using the environment,

which will be coming up as the next item in Coursera.

So you can go ahead and open that up and follow along if you want.

I'm going to go ahead and sign that I'm

going to obey the rules of Coursera honor understatement.

I'm going to do my own work.

And I'm going to click open tool,

and it gives me this window,

which basically is a Unix terminal.

So this is a thing called xterm.js.

It gives you an xterm which is a standard Unix terminal in your web browser.

Now, I'm going to make mine a little bit bigger.

So I'm going to make it like 140 columns and 36 rows,

just so I have a little more space to type.

And you'll see that it says this is my first time here.

It's setting things up and welcomes me to the practice programming environment.

Now, at this point, you're probably a little unfamiliar

with Unix and command lines and stuff.

You'll have some readings about these.

You'll get lots of practice as you go.

First thing I'm going to do is type ls which tells

Unix to list the current contents of the directory,

and we'll see that there's a read me file in a directory called learn2program.

And this learn2program directory is going to be where you'll have all your assignments.

This first one is 00 hello,

assignment zero, and the first thing we're going to do is just write a file called hello.

It's not really a programming activity but just

to get you used to these basics before you start trying to write some code.

So if I open up this file read me using emacs,

which is the editor you're going to learn to use,

it'll take it just a little second to open,

and then you'll see that there's a bunch of text here.

So I can scroll around and read this.

And as we just said,

your goal is to create a file called hello.text with one line that says hello,

and we've given you some instructions here to walk you through this.

So use emacs to open and create a new file called hello.txt,

and it says Type C-x C-f.

So in emacs speak,

this is control x control f. So going to hit control x,

and then I'm going to let go of x and hit control f. And you'll see at the bottom here,

it says find file and prompts me for the file name.

So it gives me the path that is the set of directories I'm in leading up to this,

and I can type hello.txt,

which is what I want and then hit enter.

And at the bottom, it says new file.

You can see it says hello.txt here,

which is the name of this file,

but unfortunately, I have just lost track of

my directions because they're over in that other file.

Emacs has this really cool feature that lets you look at two files at once.

So I'm going to hit control x 2.

It's going to split the buffer in half.

So I've got one buffer at the top, one buffer at the bottom.

They're both in hello.txt at this point.

Looking at two different places in one file can be really useful.

But I want to change what's open at the top so control x

b and asks me what would I like to switch to.

Read me as the default so I'm just going to hit enter.

And now I've got read me on top,

hello.txt at the bottom.

And you can see I actually had those instructions here.

And if I want to move back and forth between these control x o,

you can see my cursor is jumping between the two buffers as I hit control x o.

Okay. So, now, I want to go into this,

and I want to write the word hello,

and I'm going to hit enter so there's a new line,

which generally in files with new lines.

And then I'm going to save the file with control x control s. And you see at the bottom,

it says I wrote this file. It's now saved.

Okay. Now, I want to grade this assignment.

So what we're going to do is we're going to suspend Emacs.

I'm going to hit control z.

You'll see it says stopped Emacs read me.

Emacs is still there.

It's just kind of frozen in the background.

If wanted to bring it back because maybe I forgot to

read the instructions that were coming up,

I can type fg. It'll bring it back.

And you'll see that it tells me to run some commands with Git.

Git is a really popular revision control system.

It's used by lots of professional developers.

You'll learn about it a lot coming up.

For right now, what we're gonna do is we're going to add,

commit and push this file which puts

the file into Git and submit our works to the grader.

So I'm going to do Git add hello.txt.

It doesn't say anything.

That means everything worked correctly.

Then I'm going to say Git commit -m "Did assignment 0."

So this -m says I'm going to give my commit message on the command line.

It's just a little note about what I'm doing right now.

It says it committed it to master,

and then I'm going to do Git push.

And it sends it over to a place that it shares with the grader.

And so, now, you can see that the next thing is to grade the assignment.

So if I do grade,

it checks some stuff, make sure I've submitted all my files, runs the grader.

It says I've passed this assignment,

and it tells me that it's releasing

the next assignment and that I should continue watching

videos until I've watched the week 1 video about grading.

And that's going to cover the materials that we need to do this assignment.

It also says if I run Git pull,

I'll get my grade report and the next assignment.

So Git pull, kind of the opposite of Git push,

I'm going to get assignments that were released to me.

If you're a developing professional software you'd be

getting code that's written by your collaborators,

and you'll see that I got,

now, there's a file called grade.txt.

In this case, it just says my file match the expected output

because there's not really much that can tell me about this.

But, in general, this is where it's going to tell you which test cases you pass,

which ones you fail and something about your grade.

And so then, we have the next assignment.

We'll be ready for you to come back and do that after you've watched some more videos.

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