1. CSC128 FUNDAMENTALS OF COMPUTER PROBLEM SOLVING
PROBLEM SOLVING PHASES

2. CONTENT Program development life cycle.
Use IPO chart, Algorithm, Pseudocode, and flowchart.

3. Program Development Life Cycle (PLDC)
This methodology consist of steps programmers use to build computer programs.

4. PDLC
Analysis
Design
Implementation
Testing and debugging
Maintenance

5. STEP 1: ANALYSIS
The purpose: to describe in detail a solution to a problem and information needed in solving the problem.
How??
Study and understand the problem
Identify:
Specify the input
Specify the output
Specify the process ( formulas)

6. To bake a cake….
INPUT

7. To bake a cake….(cont.)
PROCESS

8. To bake a cake….(cont.)
OUTPUT

9. PROBLEM: To calculate and display age

10. STEP 1: ANALYSIS IPO Chart Input Process Output yearBorn
Age = currentYear - yearBorn
Age

11. STEP 2: DESIGN
Definition: it is a framework or flow that shows the step in problem solving.
Method to use:
Algorithm
Pseudocode
flowchart

12. ALGORITHM
A sequence of instruction to solve a problem, written in human language.
Get/input the year born
Calculate the age using the formula age = current year – year born
Print/ display the age

13. PSEUDOCODE
Steps in problem solving that is written in half programming code and half in human language.
For example, some part uses C++ language code and some part uses English language
Begin
Read the year born from the user.
Age = currentYear - yearBorn
Print the user age.
End

14. FLOWCHART
A representation of graphical symbols to show process or steps in problem solving.

15. Symbols
Descriptions
Terminal symbol - indicates the beginning and
end points of an algorithm.
Input-output symbol - shows an input or an output
operation.
Process symbol - shows an instruction other than
input, output or selection.
Decision symbol - shows a selection process
for two-way selection.
On-page connector - provides continuation
of logical path at another point in the same
page.
Flow lines - indicate the logical sequence of
execution steps in the algorithm

16. Flowchart Start Input year born Age = current year – year born
Print age
End

17. STEP 3: IMPLEMENTATION
The process of writing the code that translate the design into a computer program using a programming language.
Different languages have different syntax.
A language syntax’s is the set of grammar and rules that specifies how to write instructions for an algorithm.

18. Coding # include <iostream.h> void main() { int yearBorn;
int age;
int curYear ;
cout<< “please enter the current year:”;
cin>>curYear;
cout<<“please enter year born: ”;
cin>>yearBorn;
age = curYear – yearBorn;
cout<<“Your age is:”<<age; }

19. STEP 4: TESTING
The process of running the program and checking for errors. This is to ensure that the programs works like it supposed to.
Types of errors:
Syntax error
Caused by incorrectness in syntax, spelling, undeclared or undefined variables.
Run – time error
Error that occurs while program is executed with statement that requires the compiler to do something illegal, e.g. division with zero.
Logic error
Errors in logic or meaning. Output may be produced but not the right one.

20. STEP 4: TESTING Debugging
Process of locating and correcting errors in a program.

21. EDIT – COMPILE – DEBUG - LOOP
Begin
Edit program
Compile program
Compiler errors?
Test program
Run-time errors?
End
True
False
True
False

22. STEP 5: MAINTENANCE
Any activity that is designed to keep the program in working condition – modification, repairs, enhancement, replacements …
Documenting the program – useful incase of modification or maintenance.
User manual

23. Exercise: Problem 1
Write a program that will get two numbers from user. Find the summation and the display the result.

24. Exercise: Problem 2
Write a program that will get two numbers from user. Find the average and the display the result.

25. Exercise: Problem 3
To calculate the total of students in a school if the total of boy student are 501 and the total of the girl student is 700.

26. Extra exercises

27. Exercise 1
Assume that you have to write a program to calculate area of a circle using the formula given:
area = radius * radius * 3.142
a) define the input, process and output
b) draw the flowchart
c) write the pseudocode

28. Exercise 2
Write a pseudocode and a flowchart for converting temperature from Fahrenheit to Celsius. User need to input the Fahrenheit. The formula is as follow:
celsius = 5.0/9.0 * (Fahrenheit – 32.0)

29. Exercise 3
Assume that you have to write a program to calculate the area of rectangle.
Determines the input, output, process.
Draw the flowchart
Write the pseudocode