#include <stdio.h>
#include <stdlib.h>
char letter(double);

int main() { double number; char grade; printf("Please input your number grade (0-100) \n"); scanf("%lf", &number);

grade = letter(number);

printf("Your corresponding letter grade is %c\n\n", grade);

system("pause");
return 0;
}

char letter(double number){

if (number <= 60 && number >= 0)
    return 'F';
else if (number <= 69 && number >= 60)
    return 'D';
else if (number <= 79 && number >= 70)
    return 'C';
else if (number <= 89 && number >= 80)
    return 'B';
else if (number <= 100 && number >=90 )
    return 'A';
}