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How to declare an integer that can contain huge numbers like 10 in the 20th power?

How to declare an integer that can contain huge numbers like 10 in the 20th power?
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Chrysaor
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Chrysaor
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mariourkCommented:
As far as I know, a 'long int' is the largest int you can declare (doubles aside)
An 'unsigned long int is 4 bytes long. It goes from 0 to 4.294.967.295
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evilrixSenior Software Engineer (Avast)Commented:
>> An 'unsigned long int is 4 bytes long. It goes from 0 to 4.294.967.295
There is nothing in the C++ Standard that defines the size of an int.

"There are four signed integer types: signed char, short int, int, and long int. In this
list, each type provides at least as much storage as those preceding it in the list. Plain ints have the natural
size suggested by the architecture of the execution environment39) ; the other signed integer types are
provided to meet special needs."

The C99 Standard implements the type unsigned long long. The standard says this

 minimum value for an object of type long long int
LLONG_MIN -9223372036854775807 // -(263 - 1)

 maximum value for an object of type long long int
LLONG_MAX +9223372036854775807 // 263 - 1

 maximum value for an object of type unsigned long long int
ULLONG_MAX 18446744073709551615 // 264 - 1

Most modern C++ compilers will support this type, however, it is not defined in the C++ Standard (although this might change with C++09) and as such it isn't portable for use in C++ code.

http://home.att.net/~jackklein/c/inttypes.html
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Infinity08Commented:
You can always use some bignum type.
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Infinity08Commented:
For example :

        http://gmplib.org/
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