Assignment Solution

Create your own While-End (or For-End) repetition structure that includes a nested if-then selection structure. You decide the theme. You should provide both the pseudocode and the flowchart of your example. Be sure to provide an overview of what your repetition structure is doing. Provide a walk-through of your code and the values at each iteration of the loop

Details:

Program Description:

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 average exam score for each student will be calculated and printed.

Analysis:

I will use sequential and repetition programming statements. 
I will define one String to store student name: StudentName.
I will define three Float numbers: 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.


Test Plan:

To verify this program is working properly the input values could be used for testing:

Test Case
Input
Expected Output
1
Studentname=Chris
Examvalue1=80.0
Examvalue2=90.0
Examvalue3=100.0
Studentname=John
Examvalue1=70.0
Examvalue2=90.0
Examvalue3=80.0
Studentname=Sally
Examvalue1=100.0
Examvalue2=100.0
Examvalue3=100.0
Studentname=Pat
Examvalue1=50.0
Eexamvalue2=70.0
Examvalue3=60.0

Studentname=Sam
Examvalue1=90.0
Examvalue2=95.0
Examvalue3=100.0


Average for Chris is 90.0
Average for John is 80.0
Average for Sally is 100.0

Average for Pat is 60.0
Average for Sam is 95.0
Pseudocode:

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

// Declare variables
Declare StudentName as String
Declare ExamValue, Sum, Avg as Float

// Loop through 5 Students
For (students=0; students <5 ; students++)
// reset Sum to 0
Set Sum =0.0 
Print “Enter Student Name”
Input StudentName
// Nested Loop for Exams
For (exams=0; exams < 3; exams++)
Print “Enter exam grade: \n”
Input ExamValue
Set Sum = Sum + ExamValue
End For
Set Avg = Sum/3.0
Print “Average for “ + StudentName + “ is “ + Avg
End For



Flow Chart:

C Code

The following is the C Code that will compile in execute in the online compilers.

// C code

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

// Developer: Faculty CMIS102

// Date: Jan 31, 2014

#include <stdio.h

int main ()

{

/* variable definition: */

char StudentName[100];

float ExamValue, Sum, Avg;

int students,exams;

// Loop through 5 Students

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

{

// reset Sum to 0

Sum =0.0;

printf("Enter Student Name \n");

scanf("%s", StudentName);

// Nested Loop for Exams

for (exams=0; exams < 3; exams++)

{

printf ("Enter exam grade: \n");

scanf("%f", &ExamValue);

Sum = Sum + ExamValue;

}

Avg = Sum/3.0;

printf( "Average for %s is %f\n",StudentName,Avg);

}

return 0;

}

Setting up the code and the input parameters in ideone.com:

Note the Student and ExamValues for this run were:
John: 90.0 80.0 100.0
Jim: 80.0 70.0 90.0
Joe: 70.0 100.0 100.0
Sally: 100.0 95.0 91.0
Sam: 30.0 54.0 68.0 
You can change these values to any valid integer values to match your test cases.

Results from running the programming at ideone.com:

Learning Exercises for you to try:

What would you change in the design and the code if you wanted to input 10 students and 5 exams?

What is the line of code doing?


char StudentName[100];

(Hint: We haven’t covered arrays, but a String can be thought of as an array of characters) ?

What would happen if you moved the Set Sum = 0.0 from inside the for loop to right after the declaration. For example:

// Declare variables
Declare StudentName as String
Declare ExamValue, Sum, Avg as Float

// Initialize Sum
Set Sum = 0.0;

 

CODE:

// C code

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

// Developer: Faculty CMIS102

// Date: Jan 31, 2014

#include <stdio.h

int main ()

{

  /* variable definition: */

  char StudentName[100];

  float ExamValue, Sum, Avg;

  int students,exams;

   // Loop through 5 Students

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

  {

     // reset Sum to 0

     Sum =0.0; 

     printf("Enter Student Name \n");

     scanf("%s", StudentName);  

     // Nested Loop for Exams

    for (exams=0; exams < 3; exams++)

    {

        printf ("Enter exam grade: \n");

        scanf("%f", &ExamValue);

        Sum = Sum + ExamValue;

    }  

    Avg = Sum/3.0;

    printf( "Average for %s is %f\n",StudentName,Avg);

  }

  return 0;

}