Octal literals are not allowed because disallowing them discourages programmers from using leading zeros as padding in a script. For example, look at the following snippet: var eight = 0008, nine = 00009, ten = 000010, eleven = 011; console.log(eight, nine, ten, eleven); Seems harmless enough, right? We programmers with OCD just want to align … Read more
It specifies an octal (base-8) number: 0101 == 1 * (8 * 8) + 1 == 65.
All are integers, but… 1 is decimal 0 is decimal 01 is octal 00 is octal From Java Language Specification (emphasis mine): Note that octal numerals always consist of two or more digits; 0 is always considered to be a decimal numeral – not that it matters much in practice, for the numerals 0, 00, … Read more
All modern languages import this convention from C, which imported it from B, which imported it from BCPL. Except BCPL used #1234 for octal and #x1234 for hexadecimal. B has departed from this convention because # was an unary operator in B (integer to floating point conversion), so #1234 could not be used, and # … Read more
Octal is used when the number of bits in one word is a multiple of 3, or if the grouping of the bits makes sense to notate in groups of 3. Examples are ancient systems with 18bit word sizes (mostly historical) systems with 9bit bytes (mostly historical) unix file permissions with 9bits (3*3bits, “rwxr-x—” 0750) … Read more
This comes from the changes made to how integers, specifically octals, are handled in PHP7 (as oppsoed to PHP5). From the documentation (from PHP7 migration) Invalid octal literals Previously, octal literals that contained invalid numbers were silently truncated (0128 was taken as 012). Now, an invalid octal literal will cause a parse error. From the … Read more
In java, if you are defining an integer, a leading ‘0’ will denote that you are defining a number in octal int i = 07; //integer defined as octal int i = 7; // integer defined as base 10 int i = 0x07; // integer defined as hex int i = 0b0111; // integer defined … Read more
This is because when the first digit of a number (integer constant) is 0 (and second must not be x or X), the compiler interprets it as an octal number. Printing it with %d will give you a decimal value. To print octal value you should use %o specifier printf(“%o”, n); 6.4.4.1 Integer constants: An … Read more
but a leading 0 does indicate octal in many languages, as is the case here.
If you simply write 08 and 09 (without quotes) or any other numeric with a leading 0, PHP believes you’re writing an octal value, and 08 and 09 are invalid octal numbers. http://www.php.net/manual/en/language.types.integer.php Syntax Integers can be specified in decimal (base 10), hexadecimal (base 16), octal (base 8) or binary (base 2) notation, optionally preceded … Read more