structStud.c

typedef struct
{
	char fname[10];
	char lname[15];
	float perGrade;
	char letGrade;
}STUD;
typedef struct
{
	char fname[10];
	char lname[15];
	float perGrade;
	char letGrade;
}TEMP;
void enterStudents(STUD [], TEMP[]);
void sortByGPA(STUD theClass[], int);

main()
{
	STUD theClass[30];
	int scount = 0 ;
	int choice;

	printf("What would you like to do?\n");
	printf("1. Enter Students?\n");
	printf("2. Sort by name?\n");
	printf("3. Sort by GPA?\n");
	printf("0. Exit\n");
	scanf("%d",&choice);

	switch(choice)//choices
	{
		case 1:enterStudents(theClass, &scount);
			break;
		case 2:sortByName();
			break;
		case 3:sortByGPA(theClass);
			break;
		case 0:
			break;
		default:printf("Invalid input!\n\n");//default choice

	}

	
	return(0);
}

void enterStudents(STUD theClass[], int *ptr_scount )
{
	
		printf("\n Enter the last name or 0 to exit: ");
		scanf("%14[^\n]s", theClass[*ptr_scount].lname);
		fflush(stdin);

	while(theClass[*ptr_scount].lname[0]!='0')
	{
		printf("\n Enter the first name or 0 to exit: ");
		scanf("%9[^\n]s", theClass[*ptr_scount].fname);
		fflush(stdin);

		calcPercent(&theClass[*ptr_scount].perGrade);
		calcLetter(&theClass[*ptr_scount].perGrade,
					&theClass[*ptr_scount].letGrade);

		(*ptr_scount)++;
		printf("\n Enter the last name or 0 to exit: ");
		scanf("%14[^\n]s", theClass[*ptr_scount].lname);
		fflush(stdin);
	}
}
void sortByGPA(STUD theClass[])
{
	int i = 0;

		if(theClass[i].perGrade > theClass[i+1].perGrade )
		{
			TEMP = theClass[i];
			theClass[i] = theClass[i+1];
			theClass[i+1] = TEMP;
		}

}