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Conventions and declarations

Do not confuse strings in C with individual characters. By convention, individual characters are enclosed in single quotes, like this: 'a', and have the variable type char. On the other hand, string values are enclosed in double quotes, like this: "abcdefg". String variables are either arrays of type char or have the type "pointer to char", that is, char *.

Conceptually, a string is an array of characters (type char). In C, string variables can theoretically be of any length, unlike languages such as Pascal where strings hold a maximum of 255 characters. However, the length of the string value is determined by the position of the first null character ('/0') in the string. Even though a string variable might be 32,000 characters long, or longer, if the null character first appears at position 5 in the character array, the string value is considered to be of length 5 (and contains the characters in positions 0 through 4, in sequence). You will rarely need to consider this end marker, as most functions in C's string library add it or remove it automatically.