1. Problem Solving and Program Design in C (5th Edition) by Jeri R. Hanly and Elliot B. Koffman CP 202 Chapter 3 Slides By Dr. Daniyal Alghazzawi

2. CHAPTER 3 - Outline  Program 3: Calculate the Area and the Circumference  Introduction to Functions  Program 4: Performs 3 Square Root Computations  Function Prototype  Some Mathematical Library Functions  Program 5: Draw Houses using Functions

3. Program 3: Calculate the Area and the Circumference Calculate the Area and the Circumference for a circle. Area Circumference Implementation Problem Analysis Design / Algorithm TestingMaintenance 1. 2. 3. 4. 5. 6.

4. Program 3: Calculate the Area and the Circumference 1. Problem Constant: PI = 301159 2. Problem Input: circle’s radius 3. Problem Output: - Area - Circumference 4. Relevant Formula: - area = π × radius 2 - circumference = 2 π × radius ImplementationProblem Analysis Design / Algorithm TestingMaintenance 1. 2. 3. 4. 5. 6.

5. Program 3: Calculate the Area and the Circumference 1. Get the circle radius. 2. Calculate the area. (area = π × radius × radius) 3. Calculate the circumference. (circumference = 2 π × radius) 4. Display the area and the circumference. ImplementationProblemAnalysis Design / Algorithm Design / Algorithm TestingMaintenance 1. 2. 3. 4. 5. 6.

6. Program 3: Calculate the Area and the Circumference Implementation ProblemAnalysis Design / Algorithm TestingMaintenance 1. 2. 3. 4. 5. 6. Outline

7. Program 3: Calculate the Area and the Circumference

8. ImplementationProblemAnalysis Design / Algorithm Testing Maintenance 1. 2. 3. 4. 5. 6.

9. Introduction to Functions  Primary goal of Software Engineering:  Error-free code  Code reuse (using Functions)  You need to #include the file that has the functions.  For example: The function sqrt() written in the file math.h

10. Program 4: Performs 3 Square Root Computations

11. Program 4: (OUTPUT ERROR without )

12. Program 4: (OUTPUT)

13. Function Prototype Y = sqrt(x); return value - int - double - char - void function nameargument(s) - int - double - char - void function call

14. Some Mathematical Library Functions  Check TABLE 3.1 from the book.

15. Program 5: Draw Houses using Functions  Problem: We need a program that can draw 2 types of houses:  Type 1:Type 2: “Big House”“Small House” /\ *------* | | *------* /\ *------* | | *------*

16. Program 5: Draw Houses using Functions  Analysis: We need to build 3 functions:  The 1 st function is called draw_triangle() to draw:  The 2 nd function is called draw_square() to draw:  The 3 rd function is called draw_rectangle() to draw:  To draw the “Big House”, call the 1 st  2 nd functions  To draw the “Small House”, call the 2 nd  3 rd functions /\ *------* | | *------* | | *------*

17. Program 5: Draw Houses using Functions #include void draw_triangle(void) { printf("\n /\\ "); } void draw_square(void) { printf("\n *------*"); printf("\n | |"); printf("\n *------*"); } void draw_rectangle(void) { printf("\n *------*"); printf("\n | |"); printf("\n *------*"); } int main(void) { // Draw the big house draw_triangle(); draw_square(); // Draw the small house draw_triangle(); draw_rectangle(); return (0); } Using \ in the code means you have a message, such as \n. If you want to print the symbol \, you need to type it twice.

18. Program 5: (OUTPUT) #include void draw_triangle(void) { printf("\n /\\ "); } void draw_square(void) { printf("\n *------*"); printf("\n | |"); printf("\n *------*"); } void draw_rectangle(void) { printf("\n *------*"); printf("\n | |"); printf("\n *------*"); } int main(void) { // Draw the big house draw_triangle(); draw_square(); // Draw the small house draw_triangle(); draw_rectangle(); return (0); }

19. CHAPTER 3 - Conclusion  Introduction to Functions  Function Prototype  Some Mathematical Library Functions