i hove a problem about hot to write a program to determine if a number entered by a user is a prime number.

Program Input is : Prompt user for a number between 1 and 1000.

the probable Program Output is:

Echo the user input, display whether the number is a prime

number or not and the first smaller prime number and the first

bigger prime number.

my attempt to the code determine only weather the number is or not a prime number, please help me:

#include<stdio.h>

#include<math.h>

main()

{

long int a,b,c;

printf("Enter the number: ");

scanf("%ld",&a);

for (b=2;b<a;++b)

{

c= a%b;

if (c==0)

goto cool;

}

printf("\nThe number you enter is a prime number!");

goto fool;

cool: printf("\nThe number you enter is not a prime number!");

fool: printf("\n");

getch();

}