how to process multiple students in academic system

Still isn't working..

Here is my most recent code:

Code:

---

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

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

int main () {

  char moreStudents;
 
  welcome();

  while (1) {
    printf("more students (Y or N)? ");
    scanf("&#37;c", &moreStudents);
        if (!((moreStudents == 'Y')||(moreStudents == 'y'))) {
          continue;
    }
    processOneStudent();
}
  reportSummary();
  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 numStudents, studentId, class, cumulativeHours, credit, hour;
  float cumulativeGPA;
 
  numStudents = numStudents + 1;

  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", &hour, &credit);
  cumulativeGPA = ((cumulativeGPA*cumulativeHours)+(credit*hour))/(cumulativeHours+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);
  printf("\n");
}

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

---

..which yields

more students (Y or N)? n
more students (Y or N)? 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: 3.41

more students (Y or N)? more students (Y or N)?

How do I properly call the reportSummary() function when a user inputs 'N' or 'n'? And why is it printing "more students (Y or N)?" twice?

I have tried nearly EVERYTHING and I still don't understand how to write this part of the program. I would appreciate it if someone could really help to fix and explain this to me. Thanks!

> And why is it printing "more students (Y or N)?" twice?
because you still have the \n from the first time you did n<enter>, and that is being accepted into the %c in the scanf. test for it and junk the input if it's in there.

also:

Code:

---

if (!((moreStudents == 'Y')||(moreStudents == 'y'))) {
    break;
}

---

I'm not really understanding what you're talking about, but I'm trying..

Ok, the break statement allows 'N' and 'n' to call the reportSummary() function properly. So that's good..

However, after processing the first student, the program prints "more students (Y or N)?" and then automatically jumps to the function reportSummary() and exits unexpectedly. I seem to have no luck when it comes to making changes. Grrr..

Here is the main function code with the changes:

Code:

---

int main () {

  char moreStudents;
 
  welcome();

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

---

..and here is the sample run of the entire program.

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: 3.41


more students (Y or N)?
Number of students =
Number in good standing =

Thank you for using the Academic Standing System. Bye bye!

Academic Standing System has exited with status 0.

I finally figured out the solution, yes!

Thanks for all the help!

- Hugh

Quote:

---

Originally Posted by 3MGFX

I'm not really understanding what you're talking about, but I'm trying..

Ok, the break statement allows 'N' and 'n' to call the reportSummary() function properly. So that's good..

However, after processing the first student, the program prints "more students (Y or N)?" and then automatically jumps to the function reportSummary() and exits unexpectedly. I seem to have no luck when it comes to making changes. Grrr..

Here is the main function code with the changes:

Code:

---

int main () {

  char moreStudents;
 
  welcome();

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

---

..and here is the sample run of the entire program.

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: 3.41


more students (Y or N)?
Number of students =
Number in good standing =

Thank you for using the Academic Standing System. Bye bye!

Academic Standing System has exited with status 0.

---

How did you end up fixing the problem?

Code:

---

  while (1) {
    printf("\nmore students (Y or N)? ");
    scanf("%c", &moreStudents);
        if (!((moreStudents == 'Y')||(moreStudents == 'y'))) {
          break;
    }

---

I think I identified his problem. It has to do with the scanf, but what is the resolution to getting this code to work? The rest of the program worked fine. Just the infinite loop does not process the way he was expecting it to?

scanf() [and several other input methods] are good at "leaving a dangling newline" in the input buffer. You may find that a "clear the input buffer" function

Code:

---

void clearinput(void)
{
    int c;
    while((c == getchar()) != '\n' && c != EOF) ;
}

---

will solve these type of problems. Call this function before essential input, such as "do you want to do more..."

I would also write your condition as:

Code:

---

  if (tolower(moreStudents)!= 'y')  ...

---

The function tolower() takes a character and converts it to the lower case equivalent, so you don't have to worry about testing both variants.

--
Mats