I was going through few interview questions and I came across example as below. I tried the example for simple input/output and also for some logic and it works without any problems.
??=include <stdio.h>
int main(void)
??<
printf("Hello");
// Other code lines here
return 0;
??>
To my surprise, this worked without any compilation issue and output was as required.
What is the significance of '??=', '??<' and '??>' here ?
What is the significance of '??=', '??<' and '??>' here ?
??= will be replaced with #,
??< will be replaced with {,
??> will be replaced with },
by the preprocessor. These are called trigraphs. There are 9 trigraphs in total; the others are:
??( will be replaced with [,
??) will be replaced with ],
??/ will be replaced with \,
??' will be replaced with ^,
??! will be replaced with |,
??- will be replaced with ~.
Trigraphs are processed very early in the translation process, before the source code is tokenized. They can affect comments and strings and character literals.