Dev - C++ - suma de numeros binarios

#include <stdio.h>

#include <stdlib.h>

#define NUM_BITS 8

int readline(char num[][NUM_BITS]);

void binarysum(char num[][NUM_BITS], char result[]);

int main(void){

   char num[2][NUM_BITS], result[NUM_BITS+1];

   int i, j;

   if (readline(num)){

      binarysum(num, result);

      puts("");

      for (i = 0; i < 2; i++){

         printf(" ");

         for (j = 0; j < NUM_BITS; j++)

            printf("%c", '0' + num[i][j]);

         printf("\n");

      }

      for (j = 0; j < NUM_BITS+1; j++)

         printf("%c", '0' + result[j]);

      printf("\n");

      return EXIT_SUCCESS;

   }else{

      puts("Invalid input - binary numbers must contain between 1-8 characters");

      return EXIT_FAILURE;

   }

}

int readline(char num[][NUM_BITS]){

   int c, i, j, k;

   for (i = 0; i < 2; i++){

      j = 0;

      while (j < NUM_BITS && (c = getchar()) != EOF && (c == '0' || c == '1'))

            num[i][j++] = c - '0';

      if (j == NUM_BITS)

         getchar();

      if (j == 0){

         return 0;

      }else{

         for (k = NUM_BITS; k > 0; k--)

            num[i][k-1] = (j >= 1) ? num[i][--j] : 0;

      }

   }

   return 1;

}

void binarysum(char num[][NUM_BITS], char result[]){

   int i, bit_1, bit_2, carry_flag = 0;

   for (i = NUM_BITS; i > 0; i--){

      bit_1 = num[0][i-1];

      bit_2 = num[1][i-1];

      result[i] = bit_1 ^ bit_2 ^ carry_flag;

      carry_flag = (bit_1 & bit_2) | (bit_1 & carry_flag) | (bit_2 & carry_flag);

   }

   result[i] = carry_flag;

}