In c language, u usually stands for unsigned integer, that is, unsigned. In C language, there are two types of integer variables: signed integer and unsigned integer. Unsigned integers have a larger range of values than signed integers, but they cannot represent negative numbers. Generally speaking, you need to pay attention to overflow when using unsigned integers.

In c language, u can also represent Unicode characters. Unicode is a character set used to represent characters of various languages in the world in computers. Unicode characters are usually represented by 16 bits or 32 bits, where each character has a unique encoding. In c language, u is used with single quotation marks to represent Unicode characters. For example, U' Zhong' is the Unicode encoding of Chinese characters.

In c language, u can also represent unsigned short types. Unsigned short is an unsigned short integer in C language, which can store integers between 0 and 65535, that is, 16 unsigned integer. Unsigned short types are usually used when storage space needs to be limited, such as storing color values, image pixel values and so on. But it should be noted that when using unsigned short types, we should also pay attention to overflow problems.