What's the “condition” in C interview test?

Question

Would it be possible to print Hello twice using single condition?

if  \"condition\"
  printf (\"Hello\");
else
  printf(\"World\");         


        

Answer 1

Cheeting with an empty else statement:

if (condition)
    // do if stuff
else;
    // do else stuff

If you don't like the fact that else; is actually an empty else statement try this:

for (int ii=0; ii<2; ii++)
{
    if (condition && !ii)
        // do if stuff
    else
    {
        // do else stuff
        break;
    }
}

Answer 2

No love for exit?

if(printf("HelloWorld"), exit(0), "ByeBye") 
    printf ("Hello");
else
    printf ("World");

Answer 3

Solution 1:

int main(int argc, char* argv[])
{   
    if( argc == 2 || main( 2, NULL ) )
    {
        printf("Hello ");   
    }
    else
    {
        printf("World\n");
    }
    return 0;
}

Solution 2 (Only for Unix and Linux):

int main(int argc, char* argv[])
{   
    if( !fork() )
    {
        printf("Hello ");   
    }
    else
    {
        printf("World\n");
    }
    return 0;
}

Answer 4

#define CONDITION (0) if (0) {} else

or some such.

If you see such a question on an interview, run away as fast as you can! The team that asks such questions is bound to be unhealthy.

Edit - I forgot to clarify - this relies on "else" being matched with closest open "if", and on the fact that it's written as "if CONDITION" rather than if (CONDITION) - parenthesis would make the puzzle unsolvable.

Answer 5

int main()
{
    runIfElse(true);
    runIfElse(false);

    return 0;
}

void runIfElse(bool p)
{
    if(p)
    {
     // do if
    }
    else
    {
     // do else
    }
}

Answer 6

Comment the "else" ;)

if(foo)
{
    bar();
}
//else
{
    baz();
}