C Lab - CGPA

#include <stdio.h>

struct Course {
  char code[16];
  double marks;
  double credits;
};

struct Student {
  char name[64];
  double cgpa;
  int course_count;
  Course courses[10];
};

double calc_grade(double marks) {
  if(marks >= 80) {
    return 4;
  } else if(marks >= 75) {
    return 3.75;
  } else if(marks >= 70) {
    return 3.5;
  } else if(marks >= 65) {
    return 3.25;
  } else if(marks >= 60) {
    return 3;
  } else if(marks >= 55) {
    return 2.75;
  } else if(marks >= 50) {
    return 2.5;
  } else if(marks >= 45) {
    return 2.25;
  } else if(marks >= 40) {
    return 2;
  } else {
    return 0;
  }
}


int main() {
  int n;
  printf("Enter number of students: ");
  scanf("%d", &n);
  Student students[n];

  for(int i=0; i<n; i++) {
    printf("Enter student %d details:\n", i+1);
    printf("Name: ");
    scanf("%s", &students[i].name);
    printf("Number of courses: ");
    scanf("%d", &students[i].course_count);
    double total_credits = 0, qp = 0;
    for(int j=0; j<students[i].course_count; j++) {
      printf("Enter course %d details:\n", j+1);
      printf("Course code: ");
      scanf("%s", &students[i].courses[j].code);
      printf("Course credits: ");
      scanf("%d", &students[i].courses[j].credits);
      printf("Obtained marks: ");
      scanf("%lf", &students[i].courses[j].marks);
      printf("\n");
      total_credits += students[i].courses[j].credits;
      qp += students[i].courses[j].credits*calc_grade(students[i].courses[j].marks);
    }
    students[i].cgpa = qp/total_credits;
  }

  for(int i=0; i<n; i++) {
    printf("Student %d detalis:\n",i+1);
    printf("Name: %s\n", students[i].name);
    printf("CGPA: %lf\n", students[i].cgpa);
  }
}