C trigraphs, and some little tip for obfuscating

c_trigraphs_example.c

%:include <stdio.h>

main(void) ??<
	char _vls<:4:>=<%1,3,5,7%>;
	printf("val:%d ??/n", 1??(_vls??) );
??>
/*
Above code equals to following code.
Prints 3.
*/
/*
#include <stdio.h>
int main(void) {
	char _vls[4]={1,3,5,7};
	printf("val:%d \n", _vals[1] );
	return 0;
}/*

/*
More reading:
Trigraphs:
http://www.open-std.org/JTC1/sc22/wg14/www/docs/n1256.pdf § 5.1.1.2 and § 5.2.1.1
main(startup) function related:
http://www.open-std.org/JTC1/sc22/wg14/www/docs/n1256.pdf § 5.1.2.2.3
Array indexing:
http://www.open-std.org/JTC1/sc22/wg14/www/docs/n1256.pdf § 6.5.2.1 
*/