maybe some one will need it sometime :
description:
func in c++ that will add (arythmetic) two string of postive integers
to change it to c :
use malloc insted of new.
Code:
/***************************************************************************
* How to add two postive numbers?
*
* Sun Apr 22 09:25:07 2007
* Jabka Atu
*
****************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <iostream>
using namespace std;
char* add_two_postive_numbers(char *first_value,char *second_value){
char *result=NULL;
char i = 0;
char ans = '0';
char carry = 0;
char size_of_first = strlen(first_value);
char size_of_second = strlen(second_value);
char biggest_size = (size_of_first > size_of_second) ? size_of_first : size_of_second;
char smallest_size = (size_of_first < size_of_second) ? size_of_first : size_of_second;
char delta = size_of_first - size_of_second;
if (size_of_first < size_of_second)
{
result=add_two_postive_numbers(second_value,first_value);
return result;
}
result=new char[biggest_size + 2]; //one more for '\0' and for extra 1
result[biggest_size + 1] = '\0';
result[0] = '0';
for (i=0;i<size_of_second;i++)
{
ans=first_value[size_of_first - i-1] + second_value[size_of_second-i-1] + carry - '0';
carry=0;
if (ans>'9')
{
carry=1;
result[biggest_size - i] = ans - 10;
}
else
{
result[biggest_size - i] = ans;
}
}
if(!carry) //since there is an option that there
//will be no borrow i will cp it.
{
for(i = 0;i < delta; i++)
{
result[biggest_size-size_of_second - i] =
first_value[size_of_first - size_of_second - i- 1];
}
}
if (carry)
{
for (i = 0;i < (delta) ;i++)
{
ans=first_value[size_of_first - size_of_second - i - 1] + carry;
carry = 0;
if (ans > '9')
{
carry = 1;
result[biggest_size-size_of_second - i] = ans - 10 ;
}
else
{
result[biggest_size - size_of_second - i] = ans ;
}
}//end of for
if (carry)
{
result[0]='1';
}
}//end of if (exsitence of an carry
return result;
}
int main(){
char *num;
num=add_two_postive_numbers("10","100");
cout << num;
delete [] num;
return 0;
}