Write a program to Calculate Subject Marks and Percentage

  Q:-Write a program to Calculate Subject Marks and Percentage

#include <stdio.h>
 
int main(){
                float a,b,c,d,e,res;
                printf("Enter your first subject marks\n");
                scanf("%f",&a);
                if(a>100)
                {
                printf("\nPlease Enter number less than 100");
                printf("\nPlease re enter first subject marks\n");
                scanf("%f",&a);
                }
                printf("Enter your second subject marks\n");
                scanf("%f",&b);
                if(b>100)
                {
                printf("\nPlease Enter number less than 100");
                printf("\nPlease re enter second subject marks\n");
                scanf("%f",&b);
                }
                printf("Enter your third subject marks\n");
                scanf("%f",&c);
                if(c>100)
                {
                printf("\nPlease Enter number less than 100");
                printf("\nPlease re enter third subject marks\n");
                scanf("%f",&c);
                }
                printf("Enter your fourth subject marks\n");
                scanf("%f",&d);
                if(d>100)
                {
                printf("\nPlease Enter number less than 100");
                printf("\nPlease re enter fourth subject marks\n");
                scanf("%f",&d);
                }
                printf("Enter your fifth subject marks\n");          
                scanf("%f",&e);
                if(e>100)
                {
                printf("\nPlease Enter number less than 100");
    printf("\nPlease re enter fifth subject marks\n");
                scanf("%f",&e);
                }
                res=((a+b+c+d+e)*100)/500;
                                               
                if(res>=80){
                                printf("A+ grade\nand the percentage is %.2f ",res);
                }
                else if(res>=70){
                                printf("A grade \n The percentage is %.2f",res);
                }
                else if(res>=60){
                                printf("B grade \n The percentage is %.2f",res);
                }
                else if(res>=50){
                                printf("C grade \n The percentage is %.2f",res);
                }
                else {
                                printf("fail");
                }
                //printf("%f",res);
               
return 0;             
}