For any of file use this command:
gcc $CFILE -o $OUTPUTFILE && ./$OUTPUTFILE
In Linux/Windows
gcc basic-of-c/hello.c -o basic-of-c/hello && ./basic-of-c/hello
In mac
clang basic-of-c/hello.c -o basic-of-c/hello && ./basic-of-c/hello
Run function extern example
cd test-functions/extern/
gcc app.c lib.c -o app && ./app