you can not use the name of functions as the name of a variables. Function names must be different from variable names. Example: residential_rate is used both as a function name and a variable name, and since the variable name is in _tmain() the compiler is treating that symble as a float, not a function.

You are declaring functions residential_rate(), commercial_rate(), industrial_rate() also as floats of the same name in function main(). Remove those variables and it will work!

Oops, I was too slow! Sorry Mister Dragon near St Louis!

Everything worked great after taking the functions out of the identifier. Thanks!!