In C, the keyword stdio.h refers to a header file. In C, we use stdio.h because it imports various variables, macros, and functions that perform input and output operations. To perform input and output operations in our C program, we must include the stdio.h header file.
The stdio.h header file is one of the most famous in C. This file allows us to use C’s input and output functions. Because stdio.h contains over 40 functions for performing input and output operations, there are numerous ways to get and display data in C.
What is stdio.h in C?
In C, the file stdio.h is a built-in header file. The abbreviation for the terms Standard Input and Output is stdio. However, this header file includes three variables, numerous function definitions, and numerous macro definitions. In C, these variables, functions, and macros are associated with the input and output operations.
Syntax to Include stdio.h in C: #include <stdio.h>
In C, #include is a preprocessor directory. This keyword tells our program to include (or import) a header file.
Use of stdio.h
The header file stdio.h allows us to perform input and output operations in C. Printf() and scanf() are examples of functions that are used to display output and take user input, respectively. This library enables us to easily communicate with users.
The use of Streams by the stdio.h library to communicate with physical devices. A stream is a channel of communication between a program and its physical input and output devices. Additionally, the use of the standard input (stdin) stream, for example, is to read input data from a keyboard.
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Library Functions Programs of stdio.h in C
The header file <stdio.h> stands for standard input and output, and it contains a variety of library functions for input and output.
This section contains the stdio.h header file’s library functions, along with example programs and output. There is a description of each function in detail, including its definition, syntax, and program description.
List of C stdio.h Library Functions Programs
printf() function In C Language With Example
The printf() function is defined in the stdio.h header file.
Prototype: int printf(const char* str, . . .);
Parameters: const char* str, plus additional optional parameters
Return type: int
Use of function:
The printf() function outputs the arguments enclosed in double inverted quotes to the stdout stream. int printf(const char* str,…); is the prototype of the function printf().
The str pointed string contains two types of items. The first item is the data types that are displayed on the screen, and the second is the data type format. It returns the total number of characters printed or a negative value if there was an error in the output.
printf() example in C
#include <stdio.h>
int main()
{
printf("Print a character - %c\n", 'a');
printf("Print a number - %d\n", 10);
printf("Print a decimal number - %f\n", 5.25);
printf("Print a string - %s\n", "hello");
return 0;
}perror() function of stdio.h in C
This function is extremely useful because it displays the error message on the screen. All we have to do is call this function with a string parameter whenever we encounter an error.
First, it prints the String, followed by a colon, a space, and the error message.
Example:
perror(“here is the error”);
will print →
here is the error: ERROR MESSAGE.
stdio.h – perror() function Example in C
#include <stdio.h>
int main()
{
// defining the file pointer
FILE* f;
// rename file name
rename("abc.txt", "abcd.txt");
// open file
f = fopen("file.txt", "r");
// condition if error then print error
if (f == NULL) {
perror("Error in Code is: ");
return (-1);
}
// close the file
fclose(f);
return (0);
}puts() and putchar() functions of stdio.h in C
The use of the function puts() is to print strings, whereas the use of the function putchar() is to print characters, as their names imply.
These functions are from the stdio.h class and perform string-related tasks.
Example:
puts(“I AM A STRING”);
Output:
I AM A STRING
putchar(“a”);
Output:
a
You can use Printf(), which has more options than these two functions.
stdio.h – puts() and putchar() functions Example in C
#include <stdio.h>
#include <string.h>
int main()
{
// initializing the variables
char a[15];
char b[15];
char c;
// coming string in a and b
strcpy(a, "includehelp");
strcpy(b, "ihelp");
// put a and b
puts(a);
puts(b);
// printing characters
for (c = 'Z'; c >= 'A'; c--) {
putchar(c);
}
return (0);
}gets() function of stdio.h in C
The use of the function gets() is to scan a string from the user without inserting any \n or up till the \n character. This function is part of the string.h class and also doing string-related jobs.
Example:
gets(str) ;
User input: “I AM A STRING”
Output:
I AM A STRING
You can use scanf() instead, which has more options than this function.
stdio.h – gets() function Example in C
#include <stdio.h>
int main()
{
//initializing the type of variables
char str[50];
char c;
//message for user
printf("Please enter a string : ");
gets(str);
//printing the result
printf("Your String: %s\n\n", str);
//message for user
printf("Please enter a character: ");
c = getchar();
//printing the result
printf("Your Character: ");
putchar(c);
return (0);
}puts() function of stdio.h in C
The puts() function is defined in the header file stdio.h.
Prototype: int puts(const char *string);
Parameters: const char *string
Return type: int
Use of function:
We use the puts() function to write the string to the stdout output stream, which is then stored in the character array until it encounters a newline character. int puts(const char *string); is the prototype of the function puts().
String denotes the array of characters that are written to the stream. It returns a non-negative value when the operation is successful and EOF when it fails.
puts() example in C
#include <stdio.h>
int main()
{
char ch[100];
printf("Enter any string\n");
//get the string
gets(ch);
printf("\nThe string is - ");
//print the string
puts(ch);
return 0;
}This is where we end it for now. For more List of C stdio.h Library Functions Click Here.
Conclusion
In summary, the keyword “stdio.h” is a header file in C and also the stdio.h library imports Functions, variables, and macros into our program. Additionally, the functions, variables, and macros imported by stdio.h are used to perform input and output operations. Also in this article, you’ll find out that printf() and Scanf() are two(2) of the most commonly use stdio.h functions.
Hopefully, this article answered your questions on what are the functions in stdio.h and was helpful by outlining the meaning, uses, and a few library functions of stdio.h in C.
