Thread: how to process multiple students in academic system

Code:

#include <stdio.h>
#include <stdlib.h>

void welcome();
void processOneStudent();
void returnStudentData(int* studentId, int* class, int* cumulativeHours, float* cumulativeGPA);
void reportSummary(int* numStudents, int* numInGoodStanding);

int main () {

  int numStudents = 0, numInGoodStanding = 0;
  char moreStudents;
  
  welcome();
  
  printf("more students (Y or N)? ");
  scanf("&#37;c", &moreStudents);

  if ((moreStudents == 'Y')||(moreStudents == 'y')) {
    numStudents = numStudents + 1;
    processOneStudent();
  }
  
  if ((moreStudents == 'N')||(moreStudents == 'n')) {
    reportSummary(&numStudents, &numInGoodStanding);
  }
  
    return (0);

}

void welcome() {
  printf("*************************************************\n");
  printf("*    Welcome to the Academic Standing System    *\n");
  printf("*           Developed by Hugh Saddler           *\n");
  printf("*************************************************\n\n");
}

void processOneStudent() {

  int studentId, class, cumulativeHours, credit, hour;
  float cumulativeGPA;

  printf("Enter student id, class, cum. hours, cum. GPA: ");
  scanf("%d%d%d%f", &studentId, &class, &cumulativeHours, &cumulativeGPA);

  do {
  printf("Hours and grade (0 0 to end)? ");
  scanf("%d%d", &credit, &hour);
  cumulativeHours = cumulativeHours + hour;
}

  while ((credit > 0)||(hour > 0));

  if((credit == 0)||(hour == 0)) {
    returnStudentData(&studentId, &class, &cumulativeHours, &cumulativeGPA);
  }
}

void returnStudentData(int* studentId, int* class, int* cumulativeHours, float* cumulativeGPA) {
  printf("\n");
  printf("Student Id: %d\n", *studentId);
  printf("Class: %d\n", *class);
  printf("New cumulative hours: %d\n", *cumulativeHours);
  printf("New cumulative GPA: %.2f\n", *cumulativeGPA);
}

void reportSummary(int* numStudents, int* numInGoodStanding) {
  printf("\n");
  printf("Number of students = %d\n", *numStudents);
  printf("Number in good standing = %d\n", *numInGoodStanding);
  printf("\n");
  printf("Thank you for using the Academic Standing System. Bye bye!\n");
}

I want to be able to process multiple students, but my program ends after processing the first student. How do I tell the program to re-run the "more students (Y or N)?" code and keep doing so until there are no more students left and the user enters "N"?

Note: I haven't programmed to output the correct GPA, the number of students processed, and the number of students in good standing, so they may appear to be incorrect while reviewing my code. Right now, I just need help with getting the program to process multiple students instead of exiting unexpectedly. Thanks!

A while loop would be good for this. See if you can get one working for this. You could put it around this bit of code:

Code:

  printf("more students (Y or N)? ");
  scanf("%c", &moreStudents);

  if ((moreStudents == 'Y')||(moreStudents == 'y')) {
    numStudents = numStudents + 1;
    processOneStudent();
  }

Then run your report summary at the end without the if statement.

Ok.

What parameters would I use for the while loop? That's where I get confused because I thought about using a while loop a few hours ago.

I'm not sure what you mean by putting the report summary function call at the end without the if statement. I tried doing this and it doesn't respond well when a user enters 'N' or 'n'.

Why do you need the second if statement? If they don't say yes, why would you want to continue? Just put while before the first printf, and declare morestudents = 'Y'. Then leave the report summary out of the while loop and out of an if or the while, and you got what you want.

I'm still not understanding how to write the while loop that everyone is suggesting. My objective is to repeat the "more students (Y or N)?" script and continue processing more students until the user enters 'N' or 'n'. I tried rewriting my program to fit your description, but it's not allowing me to do what I want it to do. If you could post an example of the changes you're referring to, I would greatly appreciate it.

Code:

moreStudents = 'Y';
while(moreStudents == 'Y' || moreStudents == 'y'){

would be my suggestion. Put the brackets where you want it to repeat, then it will exit when the user doesn't press Y or y. If you want to specify that they have to press N or n to exit, you'll need another loop like the one above, but with N and n.

Ok.

This is what I have now:

Code:

printf("more students (Y or N)? ");
scanf("%c", &moreStudents);
  
  while ((moreStudents == 'Y')||(moreStudents == 'y')) {
    numStudents = numStudents + 1;
    processOneStudent();
}
  
    reportSummary(&numStudents, &numInGoodStanding);
  
    return (0);

It allows me to input information for another student now, but I want it to give me the option of asking the user whether or not there are more students to process. With this version of my program, it automatically assumes that there are more students and skips ahead to the processOneStudent() function. How do I get the program to prompt the user before calling that function?

And, of course, I want it to prompt the user with the original message: more students (Y or N)?

I do want to take the time to say that I appreciate it all the help that you've been giving me. Thanks!

- Hugh

Can you explain how to use this code? And what is an infinite loop?

Code:

printf("more students (Y or N)? ");
scanf("%c", &moreStudents);
  
  while ((moreStudents == 'Y')||(moreStudents == 'y')) {
    numStudents = numStudents + 1;
    processOneStudent();
    printf("more students (Y or N)? ");
    scanf("%c", &moreStudents);
      if (!((moreStudents == 'Y')||(moreStudents == 'y'))) {
        break;
      }
}
  
  if ((moreStudents == 'N')||(moreStudents == 'n')) {
    reportSummary(&numStudents, &numInGoodStanding);
}
  
    return (0);

yields..

more students (Y or N)? y
Enter student id, class, cum. hours, cum. GPA: 1001 2005 10 3.30
Hours and grade (0 0 to end)? 4 4
Hours and grade (0 0 to end)? 3 3
Hours and grade (0 0 to end)? 0 0

Student Id: 1001
Class: 2005
New cumulative hours: 17
New cumulative GPA: 3.30

more students (Y or N)?
Academic Standing System has exited with status 0.

..almost there, but it exits before allowing the user input for the next student.

Fair enough.

Now how do I incorporate that into my program so that it works properly? I posted my attempt above, and it's pretty close to what I want, but then it exits unexpectedly again..

any suggestions?

- Hugh