clrscr error in main program debug - c

Question

I am receiving the error in function main for my clrscr(); but I thought I had to clear when using fflush(stdin);?
I feel like I am missing something simple here but if anyone can shed some like I would appreciate it!
#include<stdio.h>
#include<conio.h>
#include<string.h>
struct person
{
char name[10];
int age;
};
typedef struct person NAME;
NAME stud[10], temp[10];
void main()
{
int no,i;
void sort(int N); /* Function declaration */
clrscr();
fflush(stdin);
printf("Enter the number of students in the list\n");
scanf("%d",&no);
for(i = 0; i < no; i++)
{
printf("\nEnter the name of person %d : ", i+1);
fflush(stdin);
gets(stud[i].name);
printf("Enter the age of %d : ", i+1);
scanf("%d",&stud[i].age);
temp[i] = stud[i];
}
printf("\n*****************************\n");
printf (" Names before sorting \n");
/* Print the list of names before sorting */
for(i=0;i<no;i++)
{
printf("%-10s\t%3d\n",temp[i].name,temp[i].age);
}
sort(no); /* Function call */
printf("\n*****************************\n");
printf (" Names after sorting \n");
printf("\n*****************************\n");
/* Display the sorted names */
for(i=0;i<no;i++)
{
printf("%-10s\t%3d\n",stud[i].name,stud[i].age);
}
printf("\n*****************************\n");
} /* End of main() */
/* Function to sort the given names */
void sort(int N)
{
int i,j;
NAME temp;
for(i = 0; i < N-1;i++)
{
for(j = i+1; j < N; j++)
{
if(strcmp(stud[i].name,stud[j].name) > 0 )
{
temp = stud[i];
stud[i] = stud[j];
stud[j] = temp;
}
}
}
} /* end of sort() */

Answer 1

Put the function prototype void sort(int N); outside main()
You don't have (but you may) execute clrscr() before fflush(stdin). In this case contents of your screen (which you want to clear) have nothing to do with stdin.
You can read more about fflush() and the motivation to use it, here.

Answer 2

I assume that you get a compilation error. It is caused by the line above the one where you see the error.
As suggested by #Catalyst, it is caused here by the line
void sort(int N); /* Function declaration */`
because C does not allow functions to be declared locally inside other functions (and main is a function).
You can simply fix it that way :
#include<stdio.h>
#include<conio.h>
#include<string.h>
struct person
{
char name[10];
int age;
};
typedef struct person NAME;
NAME stud[10], temp[10];
void sort(int N); /* Function declaration */
int main() // void main is incorrect
{
int no,i;
clrscr();
fflush(stdin);
...
Note also the int main() instead of void main(). It is harmless on Windows, but is still incorrect.