The statement that "plastic and long integer account for four bytes" in C language is not appropriate. In the early C compiler platform, it was 2 and 4 bytes respectively. With the upgrade of the compilation platform version, both of them are now 4 bytes, and the short one is 2 bytes. In addition, the word length of integer is not closely related to the word length of CPU: the early int was 2 bytes, but the CPU at that time was already 32 bits; Furthermore, if you install the current 4-byte int compiler platform on a 64-bit CPU machine, you can only compile 4-byte int code, not because the CPU becomes 8 bytes, but because the int in your code becomes 8 bytes. And there are no bytes in C, it's C++ ...