scanf() is a predefined function in______header file.Answer areaa) stdlib. hb) ctype. hc) stdio. hd) stdarg. H

The scanf() function is a standard input function in the C programming language, used for reading formatted input from the standard input stream (typically the keyboard).

Breakdown of Answer

1. Understanding the Function: The scanf() function is used to read user input. It facilitates various data types to be read and stored into specified variables.

2. Identifying Header Files: In C, functions are declared in header files. Each header file includes definitions and declarations for various functionalities:

   • stdlib.h: This header file contains functions related to memory allocation, process control, conversions, and others.
   • ctype.h: This header contains functions to classify characters (e.g., isalpha, isdigit).
   • stdio.h: This is the standard input-output header file that contains definitions for input-output functions, including scanf() and printf().
   • stdarg.h: This header file provides macros for handling variable argument lists.

Relevant Concepts

• Input Functions: Functions like scanf() and printf() are critical for interacting with the user and are defined in the stdio.h header file.

Analysis and Detail

Let's analyze the provided options:

• (a) stdlib.h: Incorrect - does not contain scanf().
• (b) ctype.h: Incorrect - does not contain scanf().
• (c) stdio.h: Correct - scanf() is declared in this header file.
• (d) stdarg.h: Incorrect - does not contain scanf().

Verify and Summarize

Given the analysis, it is clear that the only header file amongst the options that contains the scanf() function is stdio.h.

Final Answer

The correct answer is (c) stdio.h.