#include<stdio.h>
/*Global Variable declaration*/
int Students;
int Test;
int Quiz;
int Hwk;
int A,B,C,D,F;
int minGrade;
int maxGrade;
int classsum;
float classavg;

/*Function Prototypes*/
void introduction();
void CalculateGrade(float);
void StudAverage();
void ClassSummary();
void runMenu();
void Thankyou();

void introduction()
{
     printf("Welcome to the Gradebook Program.\n");
}
void CalculateGrade(float grade)
{
     /*if statements to find the letter grade*/
		if((grade>=90)&&(grade<=100))
			++A;
		if ((grade>=80)&&(grade<90))
			++B;
		if ((grade>=70)&&(grade<80))
			++C;
		if ((grade>=60)&&(grade<70))
			++D;
		if ((grade>=0)&&(grade<60))
			++F;
}
void StudAverage()
{
     int sum=0;
     float StudAvg=0;
     int n;
     for(n=1;n<=Students;n++)
	{
         printf("\nStudent %d\n",n);
        sum=0;
		do
		{
			printf("Enter Grade (Test):" );
			scanf("%d",&Test);
				/*test if user is entering a valid number*/
			if(Test<minGrade||Test>maxGrade)
				printf("Invalid Entry...Tray Again\n");
			}
			while(Test<minGrade||Test>maxGrade);
			/* Add test marks to sum*/
			sum = sum + Test;
		do
		{
				printf("Enter Grade (Quiz):" );
		scanf("%d",&Quiz);
				/*test if user is entering a valid number*/
			if(Quiz<minGrade||Quiz>maxGrade)
			printf("Invalid Entry...Tray Again\n");
			}
			while(Quiz<minGrade||Quiz>maxGrade);
		 			/* Add quiz marks to sum*/
			sum = sum + Quiz;
		do
		{
			printf("Enter Grade (Hwk):" );
			scanf("%d",&Hwk);
				/*test if user is entering a valid number*/
			if(Hwk<minGrade||Hwk>maxGrade)
				printf("Invalid Entry...Tray Again\n");
			}
			while(Hwk<minGrade||Hwk>maxGrade);
			/* Add Hwk marks to sum*/
			sum = sum + Hwk;
			/* Calculate & display Student Average*/
			StudAvg=sum/3;  
			printf("\nStudent Average = %.2f\n",StudAvg);
			
			/*Calculate student grade*/
			CalculateGrade(StudAvg);
			/* Calculate class sum */
			 classsum=classsum+sum;
       }//end for
      
}
void ClassSummary()
{
     int x;
     printf("\nClass Summary\n");
     /*Calculate Class average*/
     classavg=(classsum/3)/Students;
     printf("\nClass Average = %.2f",classavg);
     
     printf("\nA:%i	B:%i	C:%i	D:%i	F:%i\n",A,B,C,D,F);
	printf("\n");
	printf("\nHistorgram\n");
 /*print histograms graphically representing the counts*/
	printf("A: ");
	for (x=1;x<=A;++x)
		printf("*");
		printf("\n");
	
	printf("B: ");
	for (x=1;x<=B;++x)
		printf("*");
		printf("\n");

	printf("C: ");
	for (x=1;x<=C;++x)
		printf("*");
		printf("\n");

	printf("D: ");
	for (x=1;x<=D;++x)
		printf("*");
		printf("\n");

	printf("F: ");
	for (x=1;x<=F;++x)
		printf("*");
		printf("\n");     
}
void runMenu()
{
     int ch=0;
     do{
        printf("\nMenu\n") 	;
        printf("1 - Student Average\n");
        printf("2 - Class Summary\n");
        printf("3 - Quit\n");
        printf("Enter your choice: ");
        scanf("%d",&ch);
        switch(ch)
        {
                case 1: 
                     StudAverage();
                     break;
                case 2:
                      ClassSummary();
                      break;
                case 3:
                      return;
        }
     }while(ch!=3);
}
void Thankyou()
{
     printf("\nThank you for using Gradebook\n");
}
int main(void)
{
    introduction();
	printf("\nPlease enter the number of students: ");
	scanf("%d",&Students);
    printf("\nEnter the minimum grade allowed: ");
    scanf("%d",&minGrade);
    printf("\nEnter the maximum grade allowed: ");
    scanf("%d",&maxGrade);
    runMenu();
	Thankyou();
	system("pause");
	return 0;
}