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

Buckle your seatbelts:

#include <stdio.h>
#include <setjmp.h>

int main()
{
    jmp_buf env;

    if (!setjmp(env))
    {
        printf("if executed\n");
        longjmp(env, 1);
    }
    else
    {
        printf("else executed\n");
    }

    return 0;
}

Prints:

if executed
else executed

Is this what you mean? I doubt it, but at least it's possible. Using fork you can do it also, but the branches will run in different processes.

Answer 2

This could work:

if (printf("Hello") - strlen("Hello"))
    printf("Hello")
else
    printf("World")

This snippet emphasizes the return value of printf: The number of characters printed.

Answer 3

if  (true) printf ("Hello"); if (false)
    printf ("Hello");
else
    printf("World");

Answer 4

if(printf("Hello") == 1)
    printf("Hello")
else
    printf("World")

Answer 5

The condition to this question is:

 if(printf("hello")? 0 : 1) {   }

Answer 6

The basic answer is that in the ordinary course of events you neither want to execute both the statements in the 'if' block and the 'else' block in a single pass through the code (why bother with the condition if you do) nor can you execute both sets of statements without jumping through grotesque hoops.

Some grotesque hoops - evil code!

    if (condition == true)
    {
         ...stuff...
         goto Else;
    }
    else
    {
Else:
        ...more stuff...
    }

Of course, it is a plain abuse of (any) language because it is equivalent to:

    if (condition == true)
    {
         ...stuff...
    }
    ...more stuff...

However, it might achieve what the question is asking. If you have to execute both blocks whether the condition is true or false, then things get a bit trickier.

    done_then = false;
    if (condition == true)
    {
Then:
         ...stuff...
         done_then = true;
         goto Else;
    }
    else
    {
Else:
        ...more stuff...
        if (!done_then) goto Then;
    }