how to calculate billion number

This is a discussion on how to calculate billion number within the C++ Programming forums, part of the General Programming Boards category; i want write program to calculate billion number but when i input a lot of number my program will show ...

  1. #1
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    Exclamation 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

    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


    ps.sorry my eng is not strong.

  2. #2
    and the hat of wrongness Salem's Avatar
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    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.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  3. #3
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    Exclamation

    i use turbo c++

    thx for u help

  4. #4
    Code Goddess Prelude's Avatar
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    >i use turbo c++
    Start by getting a newer compiler. Do you have any idea how old Turbo C++ is?
    My best code is written with the delete key.

  5. #5
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    i think it came out in '91

  6. #6
    Frequently Quite Prolix dwks's Avatar
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    Exactly. For starters, use a long instead of an int.
    dwk

    Seek and ye shall find. quaere et invenies.

    "Simplicity does not precede complexity, but follows it." -- Alan Perlis
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  7. #7
    n00b programmer
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    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

  8. #8
    Registered User Bajanine's Avatar
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    How about a 'long long int' or is this not standard.
    Favorite Quote:

    >For that reason someone invented C++.
    BLASPHEMY! Begone from my C board, you foul lover of objects, before the gods of C cast you into the void as punishment for your weakness! There is no penance for saying such things in my presence. You are henceforth excommunicated. Never return to this house, filthy heretic!



  9. #9
    Cat Lover
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    long long isn't standard but it's reasonably well supported I think.

  10. #10
    and the hat of wrongness Salem's Avatar
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    Not on the OP's fossil compiler it isn't.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

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