評価

#include <stdio.h>

int main (void)
{
    int num;
    char buff[100];
    printf("input point : ");
    fgets(buff, sizeof(buff), stdin);
    sscanf(buff, "%d", &num);

    const char* hyoka = (num >= 90)
    ? "A+" :
    ((num >= 80) ? "A" :
    ((num >= 70) ? "B" :
    ((num >= 60) ? "C" : "D")));

    printf(hyoka);

    return 0;
}