C/C++
- The Setup
- First Program

C/C++

The Setup

Linux

For Debian systems like Ubuntu run this command from the command line:
```
$ sudo apt-get install build-essential
```
For RPM based Linux like Fedora, RedHat, or CentOS 7:
```
$ sudo yum groupinstall development-tools
```
p>Once installed you should be able to type:
```
$ cc --version
```

Mac OSX

Download latest XCode fro Apple or install DVD
You can also use VirtualBox and have a Linux installation and follow instructions in this tutorial

Windows

You can use Cygwin or MinGW to have standard Unix software development tools
You can also use VirtualBox and have a Linux installation and follow instructions in this tutorial (recommended)

VirtualBox

VirtualBox allows you to run an entire operating system inside another operating system. We can run Ubuntu in host Windows/Mac using VirtualBox.

Installation Process

Download and install VirtualBox from VirtualBox download page.
Launch VirtualBox from Windows Start menu.
Click New to open New Virtual Machine dialog. Name the VM, select Type and Version and click Next.
Allocate 1 GB of the RAM for the VM and click Next.
Select Create a virtual hard disk now and click Create.
Click Next.
Select Fixed Size and click Next.
Keep the default size and click Create.
Virtual Machine is created.
Goto Ubuntu download page and download ubuntu-17.04-desktop-i386.iso.
Now we need the downloaded Ubuntu disk image (the .iso) boot on the VM. Click on Settings and Storage. Then, under CD/DVD Device, next to Empty, click the Folder icon.
Select The downloaded .iso file and click OK.
Now double-click your virtual machine to start it up.
Wait for Ubuntu to boot up.

Once it starts up, follow the step by step process of Ubuntu installation.
Once installation is done, in order to use the virtualized installation (instead of continually booting the live CD), check that the CD/DVD Device entry is Empty again.
Now after restart, we should be able to login.

First Program

Setup

First we need to make sure that we have the setup for compilation and build.

Open Terminal.
Run this command from the command line:
```
$ sudo apt-get install build-essential
```
Once installed you should be able to type:
```
$ cc --version
```

Editor

Fiest of all, we are not going to use any fancy IDE. You can choose any text editor. Here are some of the options:

Atom in Windows or OSX.
Gedit on Linux and OSX.
Emacs and Emacs for OSX.
Vim in Linux.

Here, we are going to use Vim. [Tutorial for Vim.]

Install Vim

In terminal run this command:
```
$ sudo apt install vim
```
Once installed you should be able launch vim:
```
$ vim
```
Press 'i' to start insert mode and edit:
Follow Vim tutorials to learn shortcut keys

First C Program

Let us write our first program in C. Let us name the file hello.c.


  #include 

  /* This is a comment. */
  int main(int argc, char *argv[])
  {
      // this is another comment
      printf("Hello World");

      return 0;
  }

Compile and Run

In terminal run this command in the same directory where you wrote the program:
```
$ make hello
```
Now run:
```
$ ./hello
```

The first command make is a tool that knows how to build C programs. When you run it and give it hello you are telling make to look for the hello.c file, run the compiler to build it, and leave the results in a file named hello.
This hello file is an executable that you can run with ./hello, which outputs your results.

Using gcc

You can also use gcc command instead of make program to compile and build the program. In fact make program uses gcc to compile C programs.

Compiling Single Source C Program

In terminal run this command in the same directory where you wrote the program:
```
$ gcc hello.c
```
The compiler might show its messages (errors, warnings, etc.) differently, but in all cases, you'll get a file "a.out" as a result, if the compilation completed successfully. If you want the resulting program to be called "hello"
```
$ gcc -o hello hello.c
```
The '-o' flag simply name the resulting executable file as specified.

Running Executable

Once compiled and linked the program, run it by simply typing its name:
```
$ ./hello 
```
By putting './' in front of the file name, we explicitly tell our Unix shell that we want to run the program from the current directory.