#include<stdio.h>
#define STUDENTS 5

typedef struct{
    int id;
    int english;
    int class;
}Student;

void classify(Student *data);

int main(void)
{
    Student data[]={{1,60},{2,80},{3,90},{4,70},{5,50}};

    classify(data);

    for(int i=0;i<STUDENTS;i++){
        printf("id : %d, class : %c\n",data[i].id,data[i].class);
    }

    return 0;
}

void classify(Student *data)
{
    for(int i=0;i<STUDENTS;i++){
        if(data[i].english>=80){
            data[i].class='A';
        }else if(data[i].english>=70){
            data[i].class='B';
        }else if(data[i].english>=60){
            data[i].class='C';
        }else{
            data[i].class='D';
        }
    }
}