Constant too big error

This is a discussion on Constant too big error within the C++ Programming forums, part of the General Programming Boards category; I am trying to put a large number inside an int variable but I am having problems. The compiler I ...

  1. #1
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    Constant too big error

    I am trying to put a large number inside an int variable but I am having problems. The compiler I am using is microsofts visual C++ compiler v6.0.

    I get this error.

    error C2177: constant too big

    I thought that directly declaring it as an int wouldn't work because only 4 bytes is allocated to an int so I tried using new to allocate enough space.

    Code:
    int* number = new int [8];
    number = 39990881947540732160326;
    It still says constant too big.

    I tried declaring the number as type char* then using atoi and atol to convert it into a large integer but that didn't work using the code below.

    Code:
    	char* number = "39990881947540732160326";
    	int number2 = atol(number);
    	cout<<number2;
    Then I tried declaring it as a type char* again, creating an integer with new large enough to hold the correct number of bytes and then using a for loop, to move each number for the char pointer into the large int array. Like below.

    Code:
    	char* number = "39990881947540732160326";
    	int* number2 = new int [strlen(number)];
    	for(int i = 0; i < strlen(number); i++){
    		number2[i] = number[i];
    	}
    	cout<<number2;
    This still doesn't work

    I realise I over allocate space in the example above, it should be
    Code:
     strlen(number) / 4
    shouldn't it?

    But if I did that wouldn't it mean there are not enough elements of the array for me to store each number in? Like if I do it the first way isn't there enough elements but each element can hold 4 numbers right? Or should I do a nested loop inside the other loop, moving 4 numbers into one element of the array somehow, so that I can create a proper sized integer pointer so that there is not extra space allocated.

    Anyway, I can worry about proper space allocation later , if anybody can help it is appreciated.

  2. #2
    Just Lurking Dave_Sinkula's Avatar
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    Code:
    #include <iostream>
    #include <climits>
    
    int main()
    {
       std::cout << "INT_MAX = " << INT_MAX << std::endl;
       return 0;
    }
    
    /* my output
    INT_MAX = 2147483647
    */
    7. It is easier to write an incorrect program than understand a correct one.
    40. There are two ways to write error-free programs; only the third one works.*

  3. #3
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    I see.

    So as that is the maximum size for an int on my processor aswell, I will need to use another data type right?

  4. #4
    60% Braindead
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    You can try a long int:
    Code:
    long number2;
    But I dont think a long can get that big either.
    Code:
    Error W8057 C:\\Life.cpp: Invalid number of arguments in function run(Brain *)

  5. #5
    and the hat of wrongness Salem's Avatar
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    Yes, you'll need another data type.

    If you're just after an answer, then look up GMP
    http://www.swox.com/gmp/

  6. #6
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    Quote Originally Posted by Blackroot
    You can try a long int:
    Code:
    long number2;
    But I dont think a long can get that big either.
    LONG_MAX gives the same as INT_MAX.


    Quote Originally Posted by Salem
    Yes, you'll need another data type.

    If you're just after an answer, then look up GMP
    http://www.swox.com/gmp/

    I will look into it thanks.

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