Week 2 Objectives

KNOW:

• What is meant by each of the following terms: function definition, function call, function header, function body, function prototype, return type, parameter, argument, library function, user-defined function, pre-condition, post-condition, stub
• How to illustrate the inputs to and outputs from a function using a "black box"
• What happens in memory when an argument is passed by value
• The difference between file scope and block scope
• When to use a global declaration, a local declaration, or a parameter
• The difference between automatic and static storage class

BE ABLE TO:

• Write a program that calls a C library function
• Given a description for a function, draw the "black box" for that function
• Given a description for a function, write pre- and post-conditions for the function
• Given a function prototype, write a syntactically correct function call
• Given a function prototype, write the function as a stub
• Develop a complete C function definition (function heading and function body) from the description of a function
• Trace through the execution of a program that contains one or more function calls
• Show how memory is allocated for global and local variables and for parameters during program execution

Sample Quiz Questions:

1. Given this function description:

   The function named Volume uses a char called shape and two floats called dimension1 and dimension2 to determine the volume of a geometric shape. It is assumed that upon entry to the function, the value of shape is either 'C', 'Y', or 'T' (for cone, cylinder, or torus). It is also assumed that the values of dimension1 and dimension2 are greater than 0.0.

   1. Draw the function as a "black box" with inputs and outputs shown as labelled arrows. Indicate the data type associated with each arrow.
   2. Write a prototype for this function.
   3. Write a pre-condition for this function.
   4. Write the function as a stub.

2. What will be displayed when the following program executes?

   #include <stdio.h>
   
   void changeVars (int x, int y);
   
   int main()
   {
     int a=4, b=5;
     printf ("a = %d, b = %d\n", a, b);
     changeVars (a,b);
     printf ("a = %d, b = %d\n", a, b);
     return 0;
   }
   
   void changeVars (int x, int y)
   {
     x = 10;
     y = 20;
     printf ("x = %d, y = %d\n", x, y);
     return;
   }
   

3. In a short, well-written paragraph, define the terms scope and storage class.