Problem with 9999999999999999999 as a long double or long int

[lestatgirl666]

Hi

I have a problem trying to add 9999999999999999999 and -1 for example.
My result is

-8446744073709551618

The program is:

#include <stdio.h>
#include <stdlib.h>
 
int main(void)
{
   char c;
   long long sum = 0LL;
   long long num = 0LL;
   bool diff = false;
   bool suma = false;
 
   while ((c = getchar()) != EOF)
        {
                if(c == '-')
                        diff = true;
                        
                if(c == '\n')
                {
                        if(diff)
                                sum-=num;
                        else
                                sum+=num;
                                
                        printf("%lld\n", sum);
                        sum = 0;
                        num = 0;
                        suma = false;
                        diff = false;
                }
                else if((c >= '0') && (c <= '9'))
                {       
                        suma = false;
                        num*=10;
                        num += c - '0';
                }
                else if((suma == false)&&(c ==' ')){
                        if(diff)
                                sum-=num;
                        else
                                sum+=num;
                        num = 0;
                        suma = true;
                        diff = false;
                }
        }
        sum+=num;
        printf("%lld\n", sum);
 
   return EXIT_SUCCESS;
}

Thanks a lot.
Maria

[Peter87]

Run this code and see what is the maximum value long long can have. You will probably find that is is lower than 9999999999999999999.

#include <limits>
#include <iostream>
 
int main()
{
        std::cout << std::numeric_limits<long long>::max() << std::endl;
}

[lestatgirl666]

Thank you very much. Finally had to use a long double and print it with %.0Ld.
Regards,

Maria