#include <stdio.h>

int main()
{
	int x,j;
	int gradeA, gradeB, gradeC, gradeD;
	while (j != -1){
	printf("Please enter your marks (enter -1 to exit):");
	scanf("%d", &j);
			if (j >= 80 && j <= 100)
			gradeA++;

			else if (j > 60 && j < 80)
			gradeB++;

			else if (j > 40 && j < 60)
			gradeC++;

			else if (j < 40 && j > 0)
			gradeD++;

	}
	printf("%s%13s%17s\n","Grade" ,"Score", "Histogram");
	printf ("%3s%13s","A",">80");
	printf ("%10s","");
	for (x=1; x <= gradeA; x++)
	printf ("%c",'*');
	printf("\n");
	printf ("%3s%13s","B",">60");
	printf ("%10s","");
	for (x=1; x <= gradeB; x++)
	printf ("%c",'*');
	printf("\n");
	printf ("%3s%13s","C",">40");
	printf ("%10s","");
	for (x=1; x <= gradeC; x++)
	printf ("%c",'*');
	printf("\n");
	printf ("%3s%13s","D","<40");
	printf ("%10s","");
	for (x=1; x <= gradeD; x++)
	printf ("%c",'*');
	return 0;
}