Win32:TokenPasting Operator (##)

#define paster( n ) printf_s( "token" #n " = %d", token##n )
int token9 = 9;

If a macro is called with a numeric argument like

 

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paster( 9 );

the macro yields

 

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printf_s( "token" "9" " = %d", token9 );

which becomes

 

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printf_s( "token9 = %d", token9 );

Example

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

int main()
{
   paster(9);
}

token9 = 9