Have installed “Command line” but whenever i try to build and run my program terminal says “No such file or directory”
You are using the terminal incorrectly. Put double quotes around the path:

cd "/Users/Kathieen Ashley/Documents/mytest/testproject2/Debug"
## new line!
./testproject2


Don't use &amp;&amp;, they do not do what you think they do.

If you want to know more, have a look at Bash Guide for Beginners.

To elaborate a bit more on your questions:


  I have installed Command Line but somehow it doesn't work.


It seems to work just as intended, but maybe not as you intended.


  It says "no such file or directory"


cd, a command called ‘change directory’, says that there is no such directory or file as /Users/Kathieen, which is correct since your user folder seems to be
/Users/Kathieen Ashley (note the space followed by an additional word)


  but whenever I ask it to look for gcc, it tells me that I have it in my Mac.


That is correct, gcc is installed correctly.