Calculate a Student Grade

#include <stdio.h>

int main(void)
{
    double marks;

    printf("Enter marks from 0 to 100: ");
    scanf("%lf", &marks);
    if (marks < 0 || marks > 100)
        printf("Invalid marks\n");
    else if (marks >= 90)
        printf("Grade A\n");
    else if (marks >= 80)
        printf("Grade B\n");
    else if (marks >= 70)
        printf("Grade C\n");
    else if (marks >= 60)
        printf("Grade D\n");
    else
        printf("Grade F\n");
    return 0;
}