Thread: Find the sum of all the multiples of 3 or 5 below 1000.

What did you do to correct the original code?

There were several issues with the code. Please repost your corrected code. This helps others learning from your code.

Originally Posted by rstanley

What did you do to correct the original code?

There were several issues with the code. Please repost your corrected code. This helps others learning from your code.

it was a simple loop that had to be added.

Code:

#include <stdio.h>
#include <stdlib.h>
/* summing the first 1000 numbers of multiples 3 & 5 */


int main ()
{
    int c;
    int n;
    int x;
    int y, z;


    printf("");
    scanf("%d", &n);


    for (c=0; c<n; c++)
    {
        if(c%3 ==0 || c%5==0)
        {


            printf("%d \n",c);


        }  else {
                x+=c;
            }


    }
printf("%d", x);


return 0;
}

Compare the following code you your latest version, and see my comments in the code:

Code:

#include <stdio.h>
#include <stdlib.h>
/* summing the first 1000 numbers of multiples 3 & 5 */

int main (void)
{
   //Initialize all local variables
   int c = 0;
   int n = 0;
   int x = 0;

   // y & z are not used
   // int y, z;

   // Prompt the user what to enter
   printf("Please enter the upper limit\n");

   scanf("%d", &n);
   // Check here that a valid value was entered.

   for (c=0; c<n; c++)
   {
      if(c%3 ==0 || c%5==0)
      {
         printf("%d \n",c);
      }
      else
      {
         x+=c;
      }
   }

   // Print a newline at the  end
   printf("%d\n", x);

   return 0;
}

Turn on and turn up your warning level!
From my compile of your latest code:

Code:

sum.c: In function ‘main’:
sum.c:14:11: warning: zero-length gnu_printf format string [-Wformat-zero-length]
    printf("");
           ^~
sum.c:11:11: warning: unused variable ‘z’ [-Wunused-variable]
    int y, z;
           ^
sum.c:11:8: warning: unused variable ‘y’ [-Wunused-variable]
    int y, z;
        ^

Please indent your code consistently, and remove unneeded blank lines. Choose one style and be consistent.

More prompts and explanation of the program purpose, and output are needed.

Alternate implementation:

Code:

#include <stdio.h>

// Sum of values [1,n] that are divisible by d.
#define SUM_OF_DIVS(n,d) (((n)/(d))*(((n)/(d))+1)/2*(d))

int main()  {
    int n;
    printf("n: ");
    scanf("%d", &n):
    int x = SUM_OF_DIVS(n,3) + SUM_OF_DIVS(n,5) - SUM_OF_DIVS(n,15);
    printf("%d\n", x);
    return 0;
}