I think Leigh had it right, what is the problem when you did the yum install gcc ?
If you just want the sledge hammer approach and put in the group of the tools and compiler and libraries in general you can do this:
yum groupinstall "Development Tools" "Development Libraries"
I usually do that because gcc and building stuff usually requires tons of other tools: bison, make, gdb, automake, etc
so the group install just gets it over with