Why are expressions not processed after a postfix increment and a conjunction operator?

Question

I bumped into a problem which prompted me to do some research. I have found that a piece of code like this:

#include <stdio.h>

int main(void)
{
    char i = 0;
    i++ && puts("Hi!");
    printf("%hhd\n", i);
}

only processes the increment, and outputs:

1

That is not the case if the postfix increment is replaced by a prefix one, it outputs:

Hi!
1

Why does it behave like that?

I apologise if the question is dumb.

Answer 1

In

i++ &&  puts("Hi!");

i is evaluated before the increment. Because it's 0 the second part of the expression no longer needs to be evaluated, 0 && 0 is 0 , 0 && 1 is also 0 .

The same expression with a pre-increment means that i will be 1 when it's evaluated, in this case the second part of the expression is important, because 1 && 1 is possible, but 1 && 0 is also possible, and these will render different results.