How to calculate grade of student using conditional operator?

CODE

How to calculate grade of student using conditional operator?

int main()

{

    int mr;

    char gr;

    printf("\n enter the marks(out of 100):");

    scanf("%d",&mr);

    gr=((mr<=100&&mr>=95)?'O':(mr<95&&mr>=90)?'A':(mr<90&&mr>=85)?'B':(mr<85&&mr>=80)?'C':'D');

    printf("\n grade=%c",gr);

}

Output:

 enter the marks(out of 100):

98

 grade=O