ISO C trigraphs

a1.cpp

1 ??=include <stdio.h>
2 int main(int argc, char *argv[])
3 ??<
4   char ch[10]="abc";  
5   printf("trigraph test: %c\n", ch??(1??));
6   return 0;
7 ??>

g++ -ansi a1.cpp -o a1

Trigraph Sequences

Trigraph	Punctuation Character
??=	#
??(	[
??/	\
??)	]
??'	^
??<	{
??!	|
??>	}
??-	~