Sections 0101, 0102, 0103 and Honors, Fall 1995

Tuesday October 10, 1995

Assigned Reading: 5.4 - 5.5

Handouts (available on-line): none

Topics Covered:

• Traced through another example of function calls from a previous midterm exam. The question and solution.

• Reviewed the importance of using function prototypes. Here's a program that doesn't use function prototypes. Strange output is produced. The modified program works correctly when the function prototype for add3 is put in (sample run of the corrected program).

• When we use a function we should be careful to call the function with parameters that are of the same type as declared in the function's prototype. Here's a program that violates this dictum; it lets the C compiler do the type conversion. It works (see sample run), but I consider this very poor programming style. If the C compiler cannot convert the type of the actual parameter to the type of the formal parameter, as in this program, the compiler should give a compile time error.

• A function that computes the value of a raised to power b. Program and sample run.

• Using the function tested in the previous step, we write a program that rounds numbers within a given precision. Sample run.

  The meaning of functions like floor can be found in the Unix manual pages for floor by typing man floor.

• If you typed man exp in UNIX, you would have noticed that there is already a function (called pow) that computes a raised to the power b. The manual entry for "exp" begins with an explanation of "exp" for FORTRAN, ignore this.

  It is easy to modify our program which rounds real numbers so that it uses the pow function from the math library. We simply have our function call pow. Program and sample run.

• Returned Quiz 1.