0o5

0o5 is a numeric literal used to denote the octal number five in programming languages that use the 0o prefix for octal notation. The prefix "0o" (zero followed by a lowercase o) signals that the digits that follow are interpreted in base 8 rather than decimal. In octal, digits range from 0 to 7, and the value of 0o5 equals the decimal number 5.

Usage and languages

Python 3 uses the 0o prefix for octal literals, replacing the older leading-zero notation of Python 2. For example, 0o755 represents the octal number 755, commonly used to specify file permissions; in decimal, that value is 493. JavaScript added octal literals with the 0o prefix in ES6; 0o5 in JavaScript also equals 5. In C and C++, octal values can be written with a leading zero (for example 0755), but the 0o prefix is not standard in those languages. The use of 0o helps avoid confusion with decimal numbers that start with a zero in some languages.

Significance

Octal notation is historical but remains encountered in computing contexts, especially in Unix-like file permissions and legacy code. Because each octal digit maps to three binary bits, octal is a convenient compact representation for certain bit masks and permission sets. The simple value 0o5 illustrates how octal digits translate to its decimal equivalent, reinforcing the base-8 relationship.