sum of splitted digits in C

Question

I want to split the a given number (6 digits) after incrementing it by 1 into 2 numbers (3 digits for each one) then sum first 3 digits and last 3 digits and check if sum matches, do the process again, finally return the number that has the first and last 3 digits sum is equal.
My code splits the number , but the last 3 digits are printed reversed somehow (that's not the matter as I want the sum of them only) but the problem comes when I try to sum every 3 digits.

    int onceInATram(int x) {
       // Complete this function
       int n = 0;
       int y = 0;
       int len = 0;
       int digit = 0;
       int t1 = n;
       int t2 = y;
       int reminder1 = 0;
       int reminder2 = 0;
       int sum1 = 0;
       int sum2 = 0;

       len = (int) floor(log10(abs(x))) + 1;

       do {
           n = x + 1;  // to add 1 to the number
           while ((floor(log10(abs(n)) + 1) > len / 2)) {  // split it by half
               digit = n % 10;
               n = n / 10;
               y = (y * 10) + digit;
           }  

           int l = 3;
           while (l--) {
                reminder1 = t1 % 10;
                sum1 = sum1 + reminder1;
                t1 = t1 / 10;

                reminder2 = t2 % 10;
                sum2 = sum2 + reminder2;
                t2 = t2 / 10;
             }

        } while (sum1 != sum2);


         //return(printf("%d\n%d\n", n, y));  // for debugging
        return printf("%d%d\n", n, y);      // '' '' 
        //return printf("%d\n", sum1);      // '' ''
    }

    int main() {
       int x;
       scanf("%i", &x);
       int result_size;
       char* result = (char *) onceInATram(x);
       printf("%s\n", result);
        return 0;
   }

and I used function but seems that nothing work!

my input: 555555

my output: 555655 > same as 555556 (incrementing by 1 but reverse last 3 digits).

expected output: 555564 (as the sum of first 3 digits == last 3 digits).

Answer 1

I re-wrote it to try to be simpler and more straightforward.

I came up with this:

IDEOne Link:

#include <float.h>
#include <math.h>
#include <stdlib.h>

 int onceInATram(int n) {
       int y = 0;
       int x = 0;
       int t1 = n;
       int t2 = y;
       int reminder1 = 0;
       int reminder2 = 0;
       int sum1 = 0;
       int sum2 = 0;


       do {
           n = n + 1;     // to add 1 to the number
           y = n % 1000;  // This is the first 3 numbers
           x = n / 1000;  // This is the last 3 numbers

           printf("%d is now split into %d and %d\n", n, x, y);

           t1 = x;
           t2 = y;
           sum1 = 0; 
           sum2 = 0;
           for(int l=0; l<3; ++l) {
                reminder1 = t1 % 10;
                sum1 = sum1 + reminder1;
                t1 = t1 / 10;

                reminder2 = t2 % 10;
                sum2 = sum2 + reminder2;
                t2 = t2 / 10;
             }
        } while (sum1 != sum2);


        return 1000*x+y;
    }

    int main() {
       int x;
       scanf("%d", &x);
       int result = onceInATram(x);
       printf("The Final Answer is %d\n", result);
        return 0;
   }

---

Example Input / Output:

123456
The Final Answer is 123501

because 1 + 2 + 3 == 6 == 5 + 0 + 1