72a0212c_n_to_Computing_and_Programming__Goal
[Phase] Contract Purpose and Header [Activity] name the function, the classes of input data, the class of output data, and specify its purpose: ;; name : in1 in2 ...--> out ;; to compute ... from x1 ... (define (name x1 x2 ...) ...) [Goal] 
to name the function; to specify its classes of input data and its class of output data; to describe its purpose; to formulate a header
How to Design Programs: An Introduction to Computing and Programming
Goal