Escape sequences
Escape sequences are used to represent certain special characters within string literals and character constants.
# Notes
\0 is the most commonly used octal escape sequence, 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 byte or byte sequence.
Octal escape sequences have a length 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 or character constant (char, char8_t(since C23), char16_t, char32_t(since C11), or wchar_t), the result is unspecified.
A universal character name in a narrow string literal or a 16-bit string literal(since C11) may map to more than one code unit, e.g. \U0001f34c is 4 char code units in UTF-8 (\xF0\x9F\x8D\x8C)and 2 char16_t code units in UTF-16 (\xD83C\xDF4C)(since C11).
A universal character name corresponding to a code pointer greater than 0x10FFFF (which is undefined in ISO/ISC 10646) can be used in character constants and string literals. Such usage is not allowed in C++20.
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 <stdio.h>
int main(void)
{
printf("This\nis\na\ntest\n\nShe said, \"How are you?\"\n");
}