Thread: New to C any help would be great.

Hey I am learning to program in C at the moment and I'm having a few problems. I keep getting parse errors when I try to compile as well as a problem with the break statement.

Any help would be really appreciated. Thanks.

Code:

/* Check to see if a number is prime or not.
   A number is prime if it can only be dividied by itself and 1
   but by no other number.
*/

#include <stdio.h>

int main()
{
   int prime = 1;
   int number;
   int count;

   printf("Please enter a number ");
   if (scanf("%d", number) != 1)
   {
      printf("Invalid number entered\n");
      return 1;
   }
   
   for (count=1, count<number, count++);
   {
      if (number % count = 0)
      {
         break;
         prime = 0;
      }
   }
 
   if prime 
      printf("\n$d is prime\n", number);
   else
      printf("\n$d is not prime\n", number);

   return 0;
}

the problem with break statement is this that your for ends with ;.

Code:

/* Check to see if a number is prime or not.
   A number is prime if it can only be dividied by itself and 1
   but by no other number.
*/

#include <stdio.h>

int main()
{
   int prime = 1;
   int number;
   int count;

   printf("Please enter a number ");
   if (scanf("%d", &number) != 1)
   {
      printf("Invalid number entered\n");
      return 1;
   }
   
   for (count=1; count<number; count+= 2)
   {
      if ((number % count) == 0)
      {
         prime = 0;
         break;
      }
   }
 
   if (prime) 
      printf("\n%d is prime\n", number);
   else
      printf("\n%d is not prime\n", number);

   return 0;
}

Ahhhhh ok thanks very much for all your help. What is a parsing error? Is it similar to a syntax error?

Thanks once again.

Originally Posted by Desolation

You have two parsing errors and a logic error. In your for loop, you are using commas instead of semi-colons. Your last if() has no parantheses. As for the logic error, you are breaking before setting prime to 0; therefore, prime will never be set to 0. Just switch those two lines over and you should be ok.

PS: You also have $d instead of %d in your two last printf() statements.

Edit: Here's the code, you also had mixed '=' with '=='.

Code:

/* Check to see if a number is prime or not.
   A number is prime if it can only be dividied by itself and 1
   but by no other number.
*/

#include <stdio.h>

int main()
{
   int prime = 1;
   int number;
   int count;

   printf("Please enter a number ");
   if (scanf("%d", number) != 1)
   {
      printf("Invalid number entered\n");
      return 1;
   }
   
   for (count=1; count<number; count++);
   {
      if (number % count == 0)
      {
         prime = 0;
         break;
      }
   }

   if(prime)
      printf("\n%d is prime\n", number);
   else
      printf("\n%d is not prime\n", number);

   return 0;
}

check your for loop