What are the requirements for variable names in C language?

Variable names in C language can be composed of three types of characters: letters, underscores and numbers. Variable names can only start with letters or underscores. Variable names cannot be ambiguous. Variable names have length requirements, and the effective length is 3 1 character. In your name! The part exceeding the specified length will be cut off. Letters in variable names are not limited in case, but they have different case meanings.

Extended data:

Common naming methods for variable names:

1, Hungarian nomenclature, is to add several characters representing data types before each variable name. The basic principle is: variable name = attribute+type+object description. If I stands for int, then all variables starting with I stand for int type. S stands for String, and all variables whose names begin with S stand for variables of type String.

2.Camel nomenclature refers to the use of mixed uppercase and lowercase letters to form the names of variables and functions. Hump naming is similar to Pascal's, except that the first letter is lowercase, such as userName. Its name is because it looks like a hump.

3. Pascal nomenclature, that is, Pascal nomenclature. The practice is to capitalize the first letter, such as UserName, which is often used to name the variables of a class.