According to C99 standard, long long is an integer type which is at least 64-bit wide. There are two integer 64-bit types specified: long long int and unsigned long long int. So, yes, this is the biggest integer type specified by C language standard (C99 version).
So, what is a long long int?
long long and long long int are at least 64 bits. You must be using a c99 compiler or better. long is equivalent to long int , just as short is equivalent to short int . A long int is a signed integral type that is at least 32 bits, while a long long or long long int is a signed integral type is at least 64 bits.
How many bytes is a long long int?
Sizes of Fundamental Types
|bool , char , unsigned char , signed char , __int8||1 byte|
|__int16 , short , unsigned short , wchar_t , __wchar_t||2 bytes|
|float , __int32 , int , unsigned int , long , unsigned long||4 bytes|
|double , __int64 , long double , long long||8 bytes|
What is the range of long int?
A 32-bit unsigned int has a range from 0 to 4,294,967,295. 0 to 65535 would be a 16-bit unsigned. An unsigned long long (and, on a 64-bit implementation, possibly also ulong and possibly uint as well) have a range (at least) from 0 to 18,446,744,073,709,551,615 (264-1).