Printf Puzzle : Guess what should X be replaced with so as to get output as “Hello World“

#include<stdio.h>
void main()
{
if(X)
  {
   printf("Hello");
  }
else
  {
   printf("World");
  }
}

Way1 : Output

#include<stdio.h>
void main()
{
if(printf("Hello")-5)
  {
   printf("Hello");
  }
else
  {
   printf("World");
  }
}

Explanation of the Program :

  1. Printf Returns Number of Characters Printed On Screen
  2. Printf Inside “If Statement” will print “Hello” and returns Integer(number of Charcaters Printed)
  3. Subtract 5 from That number so We will get if(0) which is False Condition.
  4. Inside “else” block we are printing “world” .

Way 2 : Output :

#include<stdio.h>
void main()
{
if(!printf("Hello"))
  {
   printf("Hello");
  }
else
  {
   printf("World");
  }
}

Way 3 : Output :

#include<stdio.h>
void main()
{
if((printf("Hello") > 0 ? 0 : 1))
  {
   printf("Hello");
  }
else
  {
   printf("World");
  }
}