Strislowerabc

Strislowerabc is a hypothetical predicate used in computer science and programming examples to determine whether a given string consists solely of the lowercase letters a, b, and c. It returns true when every character in the string is one of these three letters and false otherwise. Typically, the string must be non-empty, and any other characters—uppercase letters, digits, spaces, or punctuation—cause the predicate to fail.

In practice, strislowerabc is used to illustrate concepts of character set validation, input sanitization, and regular expression construction. It differs from a general lowercase check (such as an islower test) by restricting the allowed alphabet to a fixed subset rather than the entire lowercase range.

Examples of behavior include: "abc" is true; "aabbcc" is true; "abca" is true; "ab cd" is false due to a space; "ABC" is false due to uppercase letters; an empty string is sometimes defined as false for non-empty implementations and sometimes as true depending on the convention.

Implementation notes typically describe iterating over the string and verifying that each character belongs to the set { 'a', 'b', 'c' }. This yields a time complexity of O(n) where n is the string length. An alternative is to use a regular expression such as ^[abc]+$ to perform the check in many languages. Strislowerabc serves as a focused example for validating restricted character sets and contrasts with broader string validation tools.

See also: islower, regular expressions, string validation, character classes.