signed long int
C++ signed long int will take at least 32 bits of memory to hold and cannot be less than signed int in any implementation; it can, however, differ from compiler to compiler. Signed long usually gets stored as two's complement integer, but it is not a requirement of the standard.
It can be shortened during declaration or conversion to long.
long can safely store values -2³¹ – 2³¹-1, if the value gets too large or too small, a roll over can take place. While the fact of a roll over is a guarantee at some point, a coder cannot assume that it will happen in a specific place, LONG_MIN and LONG_MAX constants from <climits> library can be used to determine that.
For most purposes when a "large number" is needed, people use long, it is also the largest built-in integer type that was available before C++11.
Other C++ data types of the same size
- unsigned long int
- char32_t (although this is not a requirement, and the program should not rely on these two being the same size, unless you know that you will not change the compiler used).
- signed int (depends upon your implementation)