the c language does not specify the number of bytes that all kinds of data occupy in the memory, but only requires that the long type data is longer than the int type and the short type data is shorter than the int type, 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, usually long is 32 bits, short is 16 bits, and int can be 16 bits or 32 bits.