Recall that the C compiler command, gcc actually invokes several other programs to transform a source file sumFirst.c file into a machine executable program file.

1. preprocessor (cpp): sumFirst.c ==> sumFirst.i

2. compiler: sumFirst.i ==> sumFirst.s

3. assembler (as): sumFirst.s ==> sumFirst.o

4. linker (ld): sumFirst.o plus other object files ==> sumFirst