Actions : Causes the corresponding actual argument to be enclosed in double quotation marks

example

int main() {
   printf_s( "In quotes in the printf function call\n" "\n" );
   printf_s( "\"In quotes when printed to the screen\"\n" "\n" );
   printf_s( "\"This: \\\" prints an escaped double quote\"" "\n" );
}

// stringizer.cpp
#include <stdio.h>
#define stringer( x ) printf( #x "\n" )
int main() {
   stringer( In quotes in the printf function call ); 
   stringer( "In quotes when printed to the screen" );   
   stringer( "This: \"  prints an escaped double quote" );
}

output

In quotes in the printf function call
"In quotes when printed to the screen"
"This: \"  prints an escaped double quote"

Actions : Causes the corresponding argument to be enclosed in single quotation marks and to be treated as a character (Microsoft Specific)

Actions : Allows tokens used as actual arguments to be concatenated to form other tokens

example

// preprocessor_token_pasting.cpp
#include <stdio.h>
#define paster( n ) printf_s( "token" #n " = %d", token##n )
int token9 = 9;

int main()
{
   paster(9);
}

output

token9 = 9

Actions : Simplifies the writing of compound expressions in certain macro directives

See TwinPages:preprocessor operator