Data Types in C++
When you create a variable, you reserve some space in memory. Different data types take up different amount of space. Some of the fundamental data types in C++ are : source : https://www.tutorialspoint.com/cplusplus/cpp_data_types.htm Calculation for range of int : 1 int contains 4 bytes and 1 byte contains 8 bits So, 1 int contains = 4x8 = 32 bits n bits can have 2^n patterns So, 32 bits have 2^32 = 4294967296, which is the range of unsigned int. Size of data types can also vary by machine.