Clear Output Screen from C program I am using a Macbook Air. I used system("cls"); and system("clear").

That would not work. It displays on the output screen (xcode output screen) that the command cannot be found. I am using the C compiler, not C++. 

How do I clear the output screen on Xcode? Please guide me through the steps in doing this.
I'm not sure I entirely follow you, however; if you are using X-Code to compile and run C programs, output (e.g. any printf statements) should automatically be sent to the console, like so:

int main(int argc, const char * argv[])
{
   printf("Test program\n");
   getchar();
   return 0;
}


Is this the 'screen' you want to clear? If so, simply building and running any program which has no console output will do so (although I'd be interested to know why you need this.)

In the example above, comment out the line with the printf statement and build and run. You'll get a clear console.