1. Selection Control Structure
CSC128: FUNDAMENTALS OF COMPUTER PROBLEM SOLVING

2. Multiple selection
To solve a problem that has several selection, use either of the following method:
Multiple selection
multiple path if
nested if

3. Multiple selection – multiple path

4. Multiple selection – multiple path
Problem statement:
Get a character from the user, if the users enter the letter ‘M’, display “Male”, else if the user enter “F” display “Female”, else display “invalid code”;

5. Multiple selection – multiple path
Pseudocode
if the code equal to ‘M’then
print “Male”
else if the code equal to ‘F’ then
print “Female
else
print “Invalid code”

6. Multiple selection – multiple path
Flowchart T
Code == ‘M’
Male F T
Code == ‘F’
Female F
Invalid code

7. Multiple selection – multiple path
if (code == ‘M’)
cout<<“Male”;
else
if (code == ‘F’)
cout<<“Female”;
cout<<“Invalid code”;
Both type of indention
is acceptable
if (code == ‘M’)
cout<<“Male”;
else if (code == ‘F’)
cout<<“Female”;
else
cout<<“Invalid code”;

8. Exercise
Write a pseudocode and flowchart for the following C++ program segment.
cin>>age;
if (age <=10)
cout<<“child”;
else if (age >10)&&(age<21)
cout<<“teenager”;
else
cout<<“adult”;

9. Exercise Can this be done??. cin>>age; if (age <=10)
cout<<“child”;
if (age >10)&&(age<21)
cout<<“teenager”;
if (age>=21)
cout<<“adult”;
A group of one-way selection

10. Exercise Problem statement:
Write a C++ program to display the program of the student based on the code the he or she inputs in the computer. Display “Invalid code” if the student enter wrong code.
Code
Program C
Computer Science A
Accounting E
Engineering

11. Exercise Problem statement:
Write a C++ program to determine the grade of a student based on the marks.
((mark>=0)&&(mark<=49))
((mark>=50)&&(mark<=64))
Atau
(mark>=75)
(mark>=65)
Marks
Program
0 -49 F
50 -64 C
65 – 74 B A

12. Multiple selection – nested if
Three shell necklaces nested together

13. Multiple selection – nested if
Problem statement:
You want to create voter eligibility program that display that displays one of three messages. The messages and the criteria for displaying each message are shown here:
Criteria
Message
Person younger than 18 years old
“you are too young to vote”
Person is at least 18 years old and is registered to vote
“you can vote”
Person is at least 18 years old but not registering to vote
“you need to register before you can vote”

14. Multiple selection – nested if
Pseudocode:
Begin
Enter age
if ( the age greater than or equal to 18)then
enter registration status
if (registration status equal to y)then
display “you can vote”
else
display “ you need to register before voting”
end if
display “you are too young to vote”
End

15. Multiple selection – nested if
Flowchart
Enter age
age
>=18
You are too young to vote
Enter registration status
status == y
You can vote
You need to register
false
true
false
true

16. Multiple selection – nested if
C++ syntax
cin>>age;
if (age < 18)
cout<<“you are too young to vote”;
else {
cin>>status;
if (status == ‘y’)
cout<<“you can vote”;
cout<<“you need to register”;
//end if
}//end if

17. Predefined function - strcmp
The strcmp are in the library with the header file string.
#include<string>

18. Predefined function - strcmp
Problem statement:
Write a C++ program to display the program of the student based on the code the he or she inputs in the computer. Display “Invalid code” if the student enter wrong code.
C++ Program segment:
if( code == ‘C’)
cout<<“ ….”;
else if ( code == ‘E’) .
Code
Program C
Computer Science A
Accounting E
Engineering

19. Predefined function - strcmp
Write a C++ program to display the code of the student based on the program the he or she inputs in the computer. Display “Invalid program” if the student enter wrong program.
Code
Program C
Computer Science A
Accounting E
Engineering

20. Predefined function - strcmp
cout<< "please enter program:";
cin.getline(program, 20);
if(program == “computer science”)
cout<<“C”;
else if (program == “Accounting”)
cout<<“A”;
else if (program == “Engineering”)
cout<<“E”;
else
cout<<“invalid”;
Is this the correct way???

21. Predefined function - strcmp
strcmp will accept two sequence of characters. It will return an integer. The integer will be:
Negative if s1 is less than s2
Zero is s1 and s2 are equal
Positive if s1 is greater than s2
int y = strcmp(s1, s2);

22. Predefined function - strcmp
How to use it???
The output:
cout<< "please enter program:";
cin.getline(program, 20);
int y = strcmp(program, “computer science”);
if(y == 0)
cout<<“yes”;
else
cout<<“no”;

23. Predefined function - strcmp
How to use it??
cout<< "please enter program:";
cin.getline(program, 20);
if(strcmp(program, “computer science”) == 0)
cout<<“yes”;
else
cout<<“no”;

24. Predefined function - strcmp
cout<< "please enter program:";
cin.getline(program, 20);
if(strcmp(program, “computer science”) == 0)
cout<<“C”;
else if (strcmp(program, “Accounting”) == 0)
cout<<“A”;
else if (strcmp(program, “Engineering”) == 0)
cout<<“E”;
else
cout<<“invalid”;

25. Thank You !