Under the early compiler, long int occupied 4 bytes, and the range of storing integers was smaller than that of int.

It belongs to long integer full name: long int short name: long.

Number of digits: the range of 32 digits is -2,147,483,648 to 2,147,483,647.

Generally speaking, integer constants are stored as int types. If the integer constant used is beyond the range of int, C language stipulates that the compiler automatically uses unsigned int to deal with this constant. If unsigned is not enough to represent this constant, the compiler will use long. If you still can't express it, then use unsigned long, long long and unsigned long in turn.