C language does not specify the number of bytes of memory occupied by all kinds of data, but only requires long data to be longer than int data and short data to be shorter than int data, which is determined by the computer system itself. Some short and int are 16 bits, long is 32 bits, some short are 16 bits, long and int are 32 bits, and long is usually 32 bits. Short is 16 bit, and int can be 16 bit or 32 bit, which are used to store integers. The binary bit length of short integers is 16, and that of long integers is 32 bits. That is, long integers can be represented by more bits. The integer range that short integers can represent is -32768~32767. Long integer is-2147483648 ~ 2147483647. For example, the number is 32780, which can only be expressed by long integers, not by short integers.