Use printf and scanf without stdio.h

Replies

• 

  [Prototype]

  Why not? Write your own printf and scanf definitions. But I don't see any reason to do so unless the curiosity bug has bitten.
• 

  Aadit Kapoor

  [Prototype]

  Why not? Write your own printf and scanf definitions. But I don't see any reason to do so unless the curiosity bug has bitten.

  You did not understand the question!I said can i call printf() and scanf() without writing up the #includes.
• 

  Sanyam Khurana

  Aadit Kapoor

  You did not understand the question!I said can i call printf() and scanf() without writing up the #includes.

  If you specifically want to call printf() and scanf() function only, then you have to add the header files. You can't skip that, because how the compiler would know where the definition of that particular function is actually is?
  
  If you don't include header files, you'll get an error for function not defined.
• 

  Nayan Goenka

  Printf() and Scanf() are predefined functions in the stdio.h file. And unless you declare and define a function, you cannot call it. So you have to include that file.
• 

  Aadit Kapoor

  No that's not correct.
  If you make a c program in turbo c++ without declaring stdio.h,you don't get an error.
• 

  Nayan Goenka

  printf() and scanf() are C language functions. generally we use cout and cin in C++.
  
  On other note, if you have included iostream.h, it may suffice.
  
  But again, I would like to see that code which helps you run printf() and scanf() without stdio.h
• 

  Nayan Goenka

  and code should not be restricted to a particular compiler. Maybe Turbo C++ auto includes stdio.h (which I don't think it does). Your code won't run on other compilers so its basically pointless.
• 

  Aadit Kapoor

  It also run on gcc compiler
  Code :
  
  Turbo c ide
  void main()
  {
  printf("hello World");
  getch();
  }
  
  Save it and run it in turbo c ide or gcc after saving it.
• 

  Ankita Katdare

  @#-Link-Snipped-# Does it give you a warning? (not error)
  
  Calling a function without declaring it will create an implicit declaration based on the parameters you give.
  In C, if you don't declare a function, and then you use it anyway, by default it returns type int. (In your case, printf and scanf both have int as their return type)
  
  From what I have read, in the beginning stage C did not have function prototypes. So feature must have been implemented for backwards compatibility.
  
  I think GCC will accept it (with a warning) because GCC does have special code to handle printf. You can check -Wformat in the manual.
• 

  Aadit Kapoor

  Thank you bhaiya's and didi's
  One more question-:
  1.What is a dummy loop in C?
• 

  Vishal Sharma

  Aadit Kapoor

  Thank you bhaiya's and didi's
  One more question-:
  1.What is a dummy loop in C?

  while(1) { }
  
  you can call this a dummy loop
• 

  Aadit Kapoor

  Vishal0203

  while(1) { }
  
  you can call this a dummy loop

  This is not a dummy loop!
  A dummy loop is
  void main()
  {
  // variables declaration
  // Here goes dummy loop
  for (i=0;i<3;i++);
  printf("Value of %d\n",i);
  getch()
  }
• 

  Vignesh Gawali

  well i think we can use printf and scanf functions without writing the include statements. This is because the linker of turbo c automatically links the standard runtime libraries during compilation of code. this option can be found in
  options->linker->libraries menu in turbo c ide.
• 

  Aadit Kapoor

  The reason that printf and scanf can be called without declaring stdio.h because in C
  Input and Output devices are directly connected to a medium i.e a device that is why it only happens with input and output functions.For other functions you have to first declare the particular header file (.h).
• 

  guptas.sneha

  There are few predefined functions in C, it allows us to call these functions without defining the prototypes.
  if you don't want to include the header you can define it as
  int printf();