0 What are identifiers in C?

Identifiers are the names that are given to various program elements, such as variables ,functions , arrays and structures . Identifiers consist of letters and digits, in any order except that first character must be a letter or an underscore. Both uppercase and lowercase letters are allowed, but it would be a good practice to use lowercase letters. Since C is a case-sensitive language ,so uppercase and lowercase letters are not interchangeable.

  An identifier can be arbitrarily long. Some implementations of C recognize only the first eight characters , though most implementations recognize more (typically 31 characters).

for example-

int number;

void Area();

char String[];