Hands-On Lab to Develop a C Program for Calculating the Average of Exam Scores

Program Description

This hands-on lab allows you to follow and experiment with the critical steps of developing a program including the program description, Analysis, , Design(program design, pseudocode), Test Plan, and implementation with C code. The example provided uses sequential, repetition statements and nested repetition statements.

This program will calculate the average of 3 exams for 5 students. The program will ask the user to enter 5 student names. For each of the students, the program will ask for 3 exam scores. The student name and the average exam score for each student will be calculated and printed. 

The program will consist of two loops. An outer loop for each student and an inner loop for the exams of each student.

I will define one String to store student name: StudentName.

I will define three Float variables: Examvalue, Sum, Avg to store exam values, the sum of the exams, and the average of

the exams.

The sum will be calculated by this formula:

Sum = Sum + Examvalue

For example, if the first value entered was 80.0 and second was 90.0 and the third exam was 100.0:

sum = sum + Examvalue = 0.0 + 80.0

sum = 80.0 + 90.0 = 170.0

sum = 170.0 + 100.0 = 270.0

Avg is then calculated as:

Avg = sum/3.0

For example 270.0/3.0 = 90.0

A nested repetition loop can be used to loop through each of the 5 students and each of the 3 exams:

For (students=0; students <5; students++)

For (exams=0;exams<3;exams++)

End For

End For

Sum values will need to be reset for each student to ensure only one student data is used for calculations each time.

Program Design (flowchart next page):

Main

// This program will calculate the average of 3 exams for 5 students

// Declare variables

// Loop through 5 Students

// reset Sum to 0

//Prompt for student name

// Nested Loop for Exams (3)

//Prompt for exam grade

2

 //Accumulate sum

//End loop For exams

//Calculate average

//Print the results studentname and average

// End loop For students

End

Learning Exercises for you to try:

1. Modify the code so that it calculates the average of 4 students with 6 exams. Hint: don’t forget to look at the average calculation. Modify the output printf statement so that the average grade is displayed with just three decimals places and so that there is two tabs between the student name and his average grade. Submit the C-code in text format in your “code” file.

2. Prepare and submit a test table(only one test case)for the code in exercise 1.Submit a screen shot of executing the code for your test case.

3. Describes what happens if you don’t have the following code Sum = 0.0 inside the for loop. Remove or comment out the line Sum = 0.0 // Sum = 0.0; Submit the C-code in text format in your “code” file.

4. Replace Sum = 0.0 back to where it was before (inside the loop). Modify the code so the user can input any number of students and any number of exams. You may assume each student has the same number of exams. Hint: you can prompt the user for the numbers and use that value OR you can use a sentinel loop approach OR you can prompt the user to continue. 

5. Modify the code to validate that the exam value is valid (i.e greater than 0and less than or equal to 110). Submit the C-code in text format in your “code”file6.

6. Prepare a new test table with at least 3 distinct test cases listing input and expected output for the code you created after step 4.