Header files in C programming

The three most important header files are given below.

1. stdio.h

This file helps your program talk to the user.

• You use it when you want to show messages on the screen or get input from the keyboard.
• It gives you tools like:
  • printf() – to print text
  • scanf() – to read what the user types

Example:
If you want the computer to say:
“Enter your name:”
and wait for the user to type something, you use stdio.h.

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2. conio.h

This file helps your program work with the keyboard and screen in a more direct way.

• It gives tools like:
  • getch() – waits for a key press (but doesn’t show what was typed)
  • clrscr() – clears the screen

This is used in old C compilers like Turbo C.
It does not work in most new compilers like GCC.

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3. math.h

This file helps your program do math.

• It gives you functions like:
  • sqrt() – to find the square root
  • pow() – to do power (like 2 to the power 3 = 8)
  • sin(), cos() – for angles and trigonometry

Example:
If you want the computer to solve √49, you use math.h and sqrt(49).