Grade of Mark in C program

#include <stdio.h>
int main(void){
int num;
printf("Enter your mark ");
scanf("%d",&num);
printf(" You entered %d", num); // printing outputs

	if(num >= 80){
	printf(" You got A grade"); // printing outputs
		}
	else if ( num >=60){ // Note the space between else & if
		printf(" You got B grade");
		}
	else if ( num >=40){
		printf(" You got C grade");
		}
	else if ( num < 40){
		printf(" You Failed in this exam");
		}
return 0;
}

Not allowing mark above 100

#include <stdio.h>
int main(void){
int num;
printf("Enter your mark ");
scanf("%d",&num);
printf(" You entered %d", num); // printing outputs
	if (num>100) printf(" ! Wrong data ");
	else if(num >= 80){
	printf(" You got A grade"); // printing outputs
		}
	else if ( num >=60){ // Note the space between else & if
		printf(" You got B grade");
		}
	else if ( num >=40){
		printf(" You got C grade");
		}
	else if ( num < 40){
		printf(" You Failed in this exam");
		}
return 0;
}

Calculating Percentage ,Average and Grade

#include<stdio.h>
#include<conio.h>

void main ()
{
	float m1,m2,m3;
	float per,avg;
	float total;
	
	printf(" enter the marks of m1 ");
	scanf("%f", &m1);
	printf(" enter the marks of m2 ");
	scanf("%f", &m2);
	printf("enter the marks of m3 ");
	scanf("%f", &m3);
	total= m1+m2+m3;
	printf("\n the total mark is %.2f ",total);
	per = (total/300)*100;
	avg = (total/3);
	printf("\n the percentage mark is : %.2f ", per);
	printf("\n the average mark  is: %.2f", avg);
	
	///// Grade calculation //
	if(per>=80) printf("\n Grade : A");
	else if(per>=60) printf("\n Grade : B");
	else if(per>=40) printf("\n Grade : C");
	else if(per<40) printf("\n Fail ");

	getch();
}