The characters in single quotes represent an integer value, such as ' A ' is a character constant, and its value is 65 in the ASCII character set;
Double quotes are string constants, such as "A" in storage: a\0, which means the end of the string with the character ' \ s '
For the escape of quotation marks and output, use the following program description:
#include <stdio.h>main () { int c; while ((C=getchar ())! = EOF) { if (c== ' \ ') */* escape character can be removed, this sentence can also be written as if (c== ' ") */ printf (" The char is: \ "\ n"); /* Escape character before the double quotation mark \ Cannot remove * /if (c== ' \ ')/ */* Single quote before the escape character \ cannot be removed * /printf ("The char is: \ \ \ n"); /* Escape character can be removed, this sentence can also be written as printf ("The char is: ' \ n"); */ }}
Simply put, if the symbols are the same, they will be escaped, and if they are different, they will not be escaped. But in order to format uniform, the quotation marks can be escaped.
Reference K&r
Quotation marks in C language--single and double quotation marks