C Program Examination result in a single subject with data validation

The program segment given below accepts marks in a single subject and uses a nested if statement to determine the validity of marks and the result if the value of marks is valid. This code can be written in a more readable form using an if-else-if statement as

#include <stdio.h>

void main()

{

     int marks;

    clrscr();

    printf(“Enter Marks of single subject  :\n”);

    scanf (“%d”, &marks);

    if (marks >= 0)

       {

             if (marks <= 100)

                {

                       if (marks >= 35)

                          printf(“Result: Pass\n”);

                          else printf(“Result: Fail\n”);

                 }

                 else printf(“Error: Marks can’t exceed 100\n”);

         }

                 else printf(“Error: Marks can’t be negative\n”);

    getch();

}