C 2: Functions and Structures

Exercise 2.1

Without writing the program, can you predict what it will print at the end? Then, write the program in functionExample.c, and confirm.

Exercise 2.2

Run the code and observe its output. Draw a memory diagram on your worksheet indicating the stack's contents just before f2() returns. (Use the stack model described above, remember to ignore printf statements). Confirm that our stack model accurately represents the program's behavior.

Change the program so that f2() is called before f1(). How does the program output change?

Revert so that f1() is called first. Then change the program so that int m is initialized to 3 in its declaration in f2(). Does our stack model still accurately represent the program behavior? If not, can you guess what the compiler is doing differently?

Revert so int m is not initialized, and int n = 4. Does our stack model still accurately represent the program behavior? If not, can you guess what the compiler is doing differently?

Exercise 2.3

What is the compiler error generated?

Add function prototypes to the top of your functionExample.c file and verify this removes compiler messages when int main is moved to the top.

Exercise 2.4

Implement the above in swapExample.c. Draw a complete memory picture just before swap() returns.

Exercise 2.5

What happens in each of the following two modifications of the swap program? Draw a complete memory diagram on your worksheet. Explain why neither of them work.

Exercise 2.6

Implement the above in structExample.c. Define another pointer based location struct called myHousePtr and make it point to the myHouse variable. Add another print statement that outputs the values for your new struct.

What errors do you get if you try to use the wrong operator to access either a pointer or non-pointer based stack?

Exercise 2.7

Add a while loop at the end to print each node's data in turn using a pointer that successively points to each node. Write your code in structExample2.c

Exercise 2.8

Fill in the worksheet memory diagram for the stack and the heap immediately before your while loop executes. You do not need to fill in addresses, but you should draw arrows showing what any pointer variables reference, or write NULL for the contents of any uninitialized pointers.

Exercise 2.9

Hand-execute the code and predict what gets printed out in your README.

Do you think static variables are stored on the stack? Why or why not?

Exercise 2.10

In mathproblem.c write a method that computes the sum

1 + 1/2 + 1/4 + ... + 1/2ⁿ

for any input parameter n.