how to calculate billion number

i want write program to calculate billion number but when i input a lot of number my program will show negative number :confused:

this my code

Code:

---

int main()
{
    double long a,b,c;
   
    scanf ("%d",&a);
    scanf ("%d",&b);
    c=a+b;
    printf("%d",c);
   
   
getch();
    }

---

why don't work?

plz help me :eek:


ps.sorry my eng is not strong.

Because normal 32 bit integers (the most common) have a max positive value of 2147483647

If you want something much bigger, tell us which compiler you're using.

i use turbo c++

thx for u help :o

>i use turbo c++
Start by getting a newer compiler. Do you have any idea how old Turbo C++ is?

i think it came out in '91

Exactly. For starters, use a long instead of an int.

int can only hold values of -32,768 through 32,767. Try compling this bit of code (Taken from SAMS Teach Yourself C++ In 24 Hours)

Code:

---

#include <iostream>

int main()
{
      int smallNumber;
      smallNumber = 32767;
      std::cout << "small number:" << smallNumber << std::endl;
      smallNumber++;
      std::cout << "small number" << smallNumber << std::endl;
      smallNumber++;
      std::cout << "small number" << smallNumber << std::endl;
      return 0;

}

---

When you see the output, you will notice that after I increment the number with ++, it wraps around to the smallest number it can hold, which is -32767. This is called (you guessed it) "Wrap Around." Use an unsigned long int for positive #s up to 4,294,967,295. Hope it helps, a fellow n00b programmer, Sintu :D

How about a 'long long int' or is this not standard.

long long isn't standard but it's reasonably well supported I think.

Not on the OP's fossil compiler it isn't.