By default, the gcc compiler names the created executable file a.out. If the -o flag is given as a command line argument to the gcc compiler, the argument immediately following the -o flag is used as the name of the created executable file.

Write the C code that would copy into a C string pointer variable execFileName the value of the command line argument immediately following the -o flag (if it is given).

• If the -o flag is NOT given, copy “a.out” into execFileName

• If there is not another command line argument after the -o flag, print out an error message as follows (just like gcc does):

   gcc: error: missing filename after '-o'

  The variable declaration for execFileName is to be:

   char* execFileName;