# include <stdio.h>

# include <stdlib.h>

# define bool int

 

int getNumeralValue(char );

char getNumeral(int );

 

/* Function to add two numbers in base 14 */

char *sumBase14(char *num1,  char *num2)

{

   int l1 = strlen(num1);

   int l2 = strlen(num2); 

   char *res;

   int i;

   int nml1, nml2, res_nml; 

   bool carry = 0;

    

   if(l1 != l2)

   {

     printf("Function doesn't support numbers of different lengths. If you want to add such numbers then prefix smaller number with required no. of zeroes");

     getchar();        

     assert(0);

   }     

 

   /* Note the size of the allocated memory is one more than i/p lengths for the cases where we have carry at the last like adding D1 and A1 */  

   res = (char *)malloc(sizeof(char)*(l1 + 1));

       

   /* Add all numerals from right to left */

   for(i = l1-1; i >= 0; i--)

   {

     /* Get decimal values of the numerals of i/p numbers*/         

     nml1 = getNumeralValue(num1[i]);

     nml2 = getNumeralValue(num2[i]);

      

     /* Add decimal values of numerals and carry */

     res_nml = carry + nml1 + nml2;

      

     /* Check if we have carry for next addition of numerals */

     if(res_nml >= 14)

     {

       carry = 1;

       res_nml -= 14;

     }   

     else

     {

       carry = 0; 

     }       

     res[i+1] = getNumeral(res_nml);

   }

       

   /* if there is no carry after last iteration then result should not include 0th character of the resultant string */

   if(carry == 0)

     return (res + 1); 

 

   /* if we have carry after last iteration then result should include 0th character */

   res[0] = '1';

   return res;

}

 

/* Function to get value of a numeral. For example it returns 10 for input 'A' 1 for '1', etc */

int getNumeralValue(char num)

{

  if( num >= '0' && num <= '9')

    return (num - '0');

  if( num >= 'A' && num <= 'D') 

    return (num - 'A' + 10);

         

  /* If we reach this line caller is giving

    invalid character so we assert and fail*/ 

  assert(0);

}

 

/* Function to get numeral for a value. For example it returns 'A' for input 10 '1' for 1, etc */

char getNumeral(int val)

{

  if( val >= 0 && val <= 9)

    return (val + '0');

  if( val >= 10 && val <= 14) 

    return (val + 'A' - 10);

     

  /* If we reach this line caller is giving

    invalid no. so we assert and fail*/     

  assert(0);

}

 

/*Driver program to test above functions*/

int main()

{

    char *num1 = "DC2";

    char *num2 = "0A3";

 

    printf("Result is %s", sumBase14(num1, num2)); 

    getchar();

    return 0;

}