What is happening in an “If(..||..)” and “If(…&&…)” construct internally?

Question

I was just wondering what happens inside of an \"if OR\" and \"if AND\". I have a feeling that it\'s just syntactic sugar to use &

Answer 1

For those who read C# better than assembly, the real internal forms are closer to:

if(a) goto yes;
if(b) goto yes;
if(c) goto yes;
goto no;
yes:  DoSomething();
goto done;
no:   /* if there were an else it would go here */;
done: ;

for

if(a || b || c)
  DoSomething();

and

if(!a) goto no;
if(!b) goto no;
if(!c) goto no;
yes:  DoSomething();
goto done;
no:   /* if there were an else it would go here */;
done: ;

for

if(a && b && c)
  DoSomething();

That's because the actual instructions are conditional branches -- in the internal form it is not possible for an if to be associated with a block, a nested if, or actually anything except a goto.