Escape sequences

Escape sequences are used to represent certain special characters within string literals and character literals.

The following escape sequences are available (extra escape sequences may be provided with implementation-defined semantics):

Notes

Of the octal escape sequences, \0 is the most useful because it represents the terminating null character in null-terminated strings.

The new-line character \n has special meaning when used in text mode I/O: it is converted to the OS-specific newline representation, usually a byte or byte sequence. Some systems mark their lines with length fields instead.

Octal escape sequences have a limit of three octal digits, but terminate at the first character that is not a valid octal digit if encountered sooner.

Hexadecimal escape sequences have no length limit and terminate at the first character that is not a valid hexadecimal digit. If the value represented by a single hexadecimal escape sequence does not fit the range of values represented by the character type used in this string literal (char, char16_t, char32_t, or wchar_t), the result is unspecified.

A universal character name in a narrow string literal or a 16-bit string literal may map to more than one character, e.g. \U0001f34c is 4 char code units in UTF-8 (\xF0\x9F\x8D\x8C) and 2 char16_t code units in UTF-16 (\uD83C\uDF4C).

If a universal character name does not correspond to a code point in ISO/IEC 10646 (the range 0x0-0x10FFFF, inclusive) or if a universal-character-name corresponds to a surrogate code point (the range 0xD800-0xDFFF, inclusive), the program is ill-formed.

The question mark escape sequence \? is used to prevent trigraphs from being interpreted inside string literals: a string such as "??/" is compiled as "\", but if the second question mark is escaped, as in "?\?/", it becomes "??/"

Example

#include <cstdio>
 
int main()
{
    std::printf("This\nis\na\ntest\n\nShe said, \"How are you?\"\n");
}

This
is
a
test
 
She said, "How are you?"

See also

• ASCII chart