C Input-Output functions - printf, scanf, putchar, getchar, gets and puts in GCC

­Input and output Functions

C language provides many in-built input-output library functions to read input and output. It is used to perform input output tasks.The standard input-output header file is stdio.h  that contains the printf() and scanf() function.

I/o Function	Description
scanf	It is used to take input through the input device.
getchar	It is used to accept a character from the console.
gets	It is used to scan a line of text from a standard input device.
printf	It is used for display output statement.
putchar	It is used to display a single character on the screen.
puts	It is used to display a string on a standard output device.

Printf() Function C Language

In C programming language, printf() function is used to print the integer,string,character, float or other value. It prints the given statement to the console.

Syntax:

            printf("format string",argument_list); 

Example 1

// C output

#include <stdio.h>    // Header File

int main(){

    printf("C Programming JavaTpoint"); 

    return 0;

}

Output

C Programming JavaTpoint

C scanf() Function C language

C  scanf() function is used as input statement. It is enclosed with double quotes. It reads the input data from the console.

Syntax:

            scanf("format string",argument_list); 

Example 1

// C Integer Input/Output

#include <stdio.h>    // Header File

int main(){

    int num;

    printf("Enter any Integer number:");

    scanf("%d",&num);

    printf("Your Integer number is :%d",num); 

    return 0;

}

Output

Enter any Integer number:567

Your Integer number is :567

Note: C language is case sensitive. For example printf() and scanf() are different from Printf() and Scanf() function. It function name must be in lowercase.

Following are the input-output format string in C Language.

Format string	Description	Example
%d	Scan or print an integer value.	45
%c	Scan or print  a single character.	‘C’
%s	Scan or print string character.	“Clanguage”
%f	Scan or print float number.	2.45
%.1f	Scan or print float number with 1 digit decimal.	10.3
%e	Scan or print a floating-point number in exponential (scientific notation).	2.000000e+000
%g	Scan or print a floating-point number in either fixed decimal or exponential format depending on the size of the number.	10.5
%lf	Scan or print double value.	20.123456
%o	Scan or print octal value.	226
%x	Scan or print hexadecimal value.	96

Some other example of printf() and scanf() function

Example 1

//  C Integer Output

#include <stdio.h>    // Header File

int main(){

    int num=786;

    printf("Your Integer number is :%d",num);  //displays the content inside quotation

    return 0;

}

Output

Your Integer number is :786

Example 2

// C Floats Input/Output

#include <stdio.h>   

int main(){

    float num;   // declare float number

    printf("Enter any Float number:");

    scanf("%f",&num);

    printf("Your Float number is :%f",num);

    return 0;

}

Enter any Float number:23.56

Your Float number is :23.559999

Example 3

// C Character I/O

#include <stdio.h>   

int main(){

    char chr;   // declare character 

    printf("Enter a character:");

    scanf("%c",&chr);

    printf("Your Enterd Character  is :%c",chr);

    return 0;

}

Output

Enter a character:J

Your Entered Character number is :J

Example 4

// C ASCII Code

#include <stdio.h>   

int main(){

    char chr;   // declare float number

    printf("Enter a character:");

    scanf("%c",&chr);

    printf("Your Entered Character  is :%c \n",chr);

    printf("ASCII value of '%c' is: %d", chr, chr); 

    return 0;

}

Output

Enter a character:A

Your Entered Character  is :A

ASCII value of 'A' is: 65

Example 5

// I/O of Floats and Integers

#include<stdio.h>

int main(){

   char ch = 'a';

   char str[15] = "javaTpoint";

   float flt = 12.334;

   int no = 150;

   double dbl = 20.123456;

   printf("Your Character is: %c \n", ch);

   printf("Your String is: %s \n" , str);

   printf("Your Float value is: %.3f \n", flt);

   printf("Your Integer value is: %d\n" , no);

   printf("Your Double value is: %lf \n", dbl);

   printf("Your Octal value is %o: \n", no);

   printf("Your Hexadecimal value is: %x \n", no);

   return 0;

}

Output

Your Character is: a

Your String is: javaTpoint

Your Float value is: 12.334

Your Integer value is: 150

Your Double value is: 20.123456

Your Octal value is 226:

Your Hexadecimal value is: 96

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Getchar() Function 

The getchar() function is used to accept a character from the console and display output immediately while typing  or press any key for proceeding.

Syntax:

                        getchar(void);

Function	Parameter
getchar()	It read a single character from the input device and return  unsigned char.

Example 1

#include<stdio.h>

int main(){

char a;

printf("Enter a character:");

a=getchar(); // take input a single character

printf("Given character is %c:",a);

return 0;

}

Output

Enter a character:C

Given character is C: