Question

Suppose you are writing a program to compute the semester GPA for a person based on knowing the grades earned and the number of credit hours for each course taken.

What type of tests would you need to create to check that your program was working correctly? Be specific, and remember to keep in mind tests that might contain unexpected input. How would your program react to those?

After you have made your post, you need to provide thoughtful comments on at least two other posts (or replies).

Your original post is due Sep 8; your replies are due Sep 11.

Answer 1

In order to test a program, we must know how to calculate GPA from grades and credit hours.

Following is the common grades according to Grade point achieved.

Grade Point	Grade
4.00	A+
3.67	A-
3.33	B+
3.00	B
2.67	B-
2.33	C+
2.00	C
1.00	D
0.00	F

From the grades of subjects, grade points are taken using above table

Subject	Grades	Credit Hours	GradePoint
English	A+	2	4.00
EVS	B	3	3.00
Maths	C+	4	2.33

to calculate GPA from credit hours, Credit hours is multiplied with GradePoint to get GP

Subject	Grades	Credit Hours	GradePoint	GP
English	A+	2	4.00	8.00
EVS	B	3	3.00	9.00
Maths	C+	4	2.33	9.32
Sum		9		26.32

GPA = Sum of GP/sum of credit Hours

                = 26.32/9

                =2.92

Algorithm to calulate GPA

1. Display “Enter English Grade “
2. Accept Enggrade
3. Display “Enter English Credit Hours “
4. Accept EngCR
5. Display “Enter EVS Grade “
6. Accept EVSgrade
7. Display “Enter EVS Credit Hours “
8. Accept EVSCR
9. Display “Enter Mathematics Grade “
10. Accept Mgrade
11. Display “Enter Maths Credit Hours “
12. Accept MathsCR
13. EngGP=checkgrade(Enggrade)
14. If EngGP == -1

Display “Invalid Input

Exit program

                End if

15. EVSGP=checkgrade(EVSgrade)
16. If EVSGP == -1

Display “Invalid Input

Exit program

                End if

17. MathsGP=checkgrade(Mgrade)
18. If MathsGP == -1

Display “Invalid Input

Exit program

                End if

19. Eng=EngGP * EngCR
20. EVS=EVSGP * EVSCR
21. Maths=MathsGP *MathsCR
22. SumCR=EngCR + EVSCr + MathsCR
23. SumGP= Eng + EVS + Maths
24. GPA = SumGP / SumCR
25. End

Funtion checkgrade(grade)

If grade==”A+”

return 4.00

else if grade==”A-“

                return 3.67

else if grade==”B+”

                return 3.33

else if grade==”B”

                return 3.00

else if grade==”B-“

                return 2.67

else if grade==”C+”

                return 2.33

else if grade== “C”

                return 2.00

else if grade==”D”

                return 1.00

else if grade== “F”

                return 0.00

else

                return -1

End If

End Function

Types of testing

For GPA program

1. Cheking of if-else structure of function checkgrade for correctness according to table.

Example : A simple value change such as 2.34 instead of 2.33 for “C+” will give wrong results

2. Check for formulas used according to method from point 19 to 24
3. Correctness of datatype used. In this case float should be used and not int for calculations and storing numeric values.
4. Checking input correctness.

Some examples of unexpected inputs:

1. Inputing grade not used in if –else.

This can be dealt using extra else and returning some exit value which is checked and program exits as shown in algorithm.

2. Input character in credit hours- algorithm must check input entered is numeric or not and keeps on asking input till number entered
3. Input incorrect : This is human error where credit hours or grades are wrongly entered