C

finding average of elements in array using struct in C?

typedef struct Student{
    int student_marks;
    int Rno;
    char name[40];


} st;


int average(struct Student ptr[], int n);

int main(){
    //int marks[10];

    struct Student st[20];
    // = {{154, 12,"john"}, {212, 43, "Mike"}, {124,53,"James"}};
    for (int j = 0; j < 20; ++j){
        scanf("%s %d %d", st.name, st.Rno, st.student_marks)
    }
    printf("Student Average is : %d
", average(s,3));

    return 0;
}



int average(struct Student *ptr, int n){
     int sum = 0, agf, n;

    //int len = sizeof(mr)/sizeof(mr[0]);
    for (int i = 0; i <= 3; i++){
        sum += ptr[i];
    }

    agf = sum / n;

}