Search results
Results from the WOW.Com Content Network
In computer science, an illegal character is a character that is not allowed by a certain programming language, protocol, or program. [1] To avoid illegal characters, some languages may use an escape character which is a backslash followed by another character.
find_character(string,char) returns integer Description Returns the position of the start of the first occurrence of the character char in string. If the character is not found most of these routines return an invalid index value – -1 where indexes are 0-based, 0 where they are 1-based – or some value to be interpreted as Boolean FALSE.
Generally, an escape character is not a particular case of (device) control characters, nor vice versa.If we define control characters as non-graphic, or as having a special meaning for an output device (e.g. printer or text terminal) then any escape character for this device is a control one.
The length of a string is found by searching for the (first) NUL. This can be slow as it takes O(n) (linear time) with respect to the string length. It also means that a string cannot contain a NUL (there is a NUL in memory, but it is after the last character, not in the string).
A string literal or anonymous string is a literal for a string value in the source code of a computer program. Modern programming languages commonly use a quoted sequence of characters, formally "bracketed delimiters", as in x = "foo" , where , "foo" is a string literal with value foo .
In C and many derivative programming languages, a string escape sequence is a series of two or more characters, starting with a backslash \. [3]Note that in C a backslash immediately followed by a newline does not constitute an escape sequence, but splices physical source lines into logical ones in the second translation phase, whereas string escape sequences are converted in the fifth ...
The text editor could replace this byte with the replacement character to produce a valid string of Unicode code points for display, so the user sees "f r". A poorly implemented text editor might write out the replacement character when the user saves the file; the data in the file will then become 0x66 0xEF 0xBF 0xBD 0x72.
The ability to represent a null character does not always mean the resulting string will be correctly interpreted, as many programs will consider the null to be the end of the string. Thus the ability to type it (in case of unchecked user input ) creates a vulnerability known as null byte injection and can lead to security exploits.