Question

What is the meaning of the below code? I thought that it is compilation error. But no compilation error occurs.

int main() 
{ 
    const int a=1; 
    printf("%c", ++a["Gyantonic"]); 
}

Output in Linux a is segmentation fault. It gives a compilation error if a[1] is given in place of ++a["Gyantonic"].

How does it work?

Answer 1

 ++a["Gyantonic"]

is equivalent to:

++(a["Gyantonic"])

which is equivalent to

++("Gyantonic"[a])

equivalent to

++("Gyantonic"[1])

"Gyantonic"[1] yields 'y' and the ++ increments the 'y' stored in the string literal and yields the result. But "Gyantonic" is a string literal and string literals cannot be modified. This is why you get the segmentation fault.