Student record using Structure in c

/*WAP of Student record using Structure in c*/

#include<stdio.h>
#include<conio.h>
struct student
{
 int rollno, marks1,marks2,marks3,tot;
 char name[25],grade;
 float per;
};
void main()
{
 struct student s;  //Data type of '*s' is struct student
 clrscr();
 //take input from user
 printf("Enter Student Roll Number: ");
 scanf("%d", &s.rollno);
 printf("\nEnter Student name: ");
 scanf("%s", s.name);
 printf("\nEnter Student 3 subject's marks: ");
 scanf("%d%d%d", &s.marks1,&s.marks2,&s.marks3);
 //calculation
 s.tot = s.marks1 + s.marks2 + s.marks3;
 s.per = s.tot/3;
 if(s.per>=75){
  s.grade = 'A';
 }
 else if(s.per<75 && s.per>=60){
  s.grade = 'B';
 }
 else if(s.per<60 && s.per>=50){
  s.grade = 'C';
 }
 else if(s.per<50 && s.per>=40){
  s.grade = 'D';
 }
 else if(s.per<40 && s.per>=33){
  s.grade = 'E';
 }
 else {
  s.grade = 'F';
 }
 //Display result
 printf("\n==================================\n");
 printf("\nStudent's Roll no. - %d", s.rollno);
 printf("\nStudent's Name - %s", s.name);
 printf("\nStudent's Total Marks - %d", s.tot);
 printf("\nStudent's Percentage - %f", s.per);
 printf("\nStudent's Grade - %c", s.grade);

 getch();
}