 In this video we're going to show you how to test your C programs with the compiler inside the virtual machine. What you need is the virtual machine installed and executed, a command interpreter, a compiler and we'll use the text editor key. The objective is to prepare the environment to make fast tests on your C programs. We recommend you do that not only for the project but also when you are studying any C programming language construction, write your own program. We start by creating a window with a command interpreter. We put it on the right-hand side of the screen and on the left-hand side we open the CATE editor with the icon at the bottom of the panel. Then we write a simple C program, a small include directive at the top and then a short main function to execute a trivial program in which we only declare two integral variables, one of them unsigned, the other one signed. We assign it to zero and then we write a simple statement. We save the file with Ctrl S or the icon at the top of the editor and we save it in the documents folder with the name tmp.c. We move over the interpreter window. With the cd command we change to the documentus folder and in there we can see with the ls command we have the tmp.c. We compile the file with this command gcc-w all-so-program space tmp.c and we get an error that is telling us that main should be of type integer and not return and avoid. We go back to the editor, modify the file, save again with the app arrow, we recover the command, execute again and now another warning pops up at line 9 telling us that the function reaches the end and there is no result being returned. We fix that with a return statement return zero. Save again, app arrow recovers the compile command, we compile and nothing appears which means the executable has been created with the name program and we execute it with .slash program. Let's undo these changes and repeat exactly the same steps but in this case using the compilation from within the editor, which is in the build menu. There we see the quick compile, if we ask for that again, warning on line 3, double click on the error line, brings the editor to that line, we save again, alt C can also be used to compile exactly the same quick compile, warning on line 9, fix it again the same way with the return statement, Ctrl S to save, alt C to compile, no errors, the program is correct.