Formatted Input and Output in C with Example

Input and Output in C – Input refers to the act of providing data to software.

A file or the command line can be used to provide an input.

The built-in functions in C programming make it possible to read the input and pass it along to the program as needed.

The term “output” refers to the presentation of data in a file, on the screen, or on a printer.

A collection of built-in functions for C programming are available to output data to the computer screen as well as save it to text or binary files.

Standard Files

Every device is treated as a file in C programming.

In order to allow access to the keyboard and screen while a program runs, the following three files are automatically opened.

Devices like the display are thus accessed in the same way as files.

Example 1 of Output in C

#include <stdio.h>    
int main()
{ 
    // Displays the string inside quotations
    printf("C Programming Tutorial in Input and Output");
    return 0;
}

Output of the above example:

C Programming Tutorial in Input and Output

How does this program work?

• The main() function must be present in every legitimate C program. The main() function is where the code execution starts.

• A library function called printf() is used to display formatted output on screens. The string is printed within quote marks by the function.

• We must use the #include stdio.h> declaration to include the stdio.h header file in order to use printf() in our application.

• The main() function’s return 0; line represents the program’s “Exit status.” It’s not required.

You can test the above example here! ➡ C Online Compiler

Example 2 of Integer Output in C

#include <stdio.h>
int main()
{
    int exampleInteger = 45;
    printf("Number = %d", exampleInteger);
    return 0;
}

Output of the above example:

Number = 45

To print int types, we utilize the percent d format specifier.

Here, the value of exampleInteger will be used in place of the percentage d enclosed in quote marks.

You can test the above example here! ➡ C Online Compiler

Example 3 of float and double Output in C

#include <stdio.h>
int main()
{
    float testnum1 = 45.5;
    double testnum2 = 35.4;
    printf("number1 = %f\n", testnum1);
    printf("number2 = %lf", testnum2);
    return 0;
}

Output of the above example:e

number1 = 45.500000
number2 = 35.400000

We utilize the percent %f format specifier to output float. In the same manner, we print double numbers by using percent %lf.

You can test the above example here! ➡ C Online Compiler

Example 4 of Print Characters in C Output

#include <stdio.h>
int main()
{
    char chr = 'x';    
    printf("character = %c", chr);  
    return 0;
} 

Output of the above example:

character = x

We employ the percent %C format specifier to print char.

You can test the above example here! ➡ C Online Compiler

Input in C

One of the often used functions in C programming to receive user input is scanf().

Using common input devices like keyboards, the scanf() function reads formatted input.

Example 5 of Integer Input and Output in C

#include <stdio.h>
int main()
{
    int exampleInteger;
    printf("Enter an integer: ");
    scanf("%d", &exampleInteger);  
    printf("Number = %d",exampleInteger);
    return 0;
}

Output of the above example:

Enter an integer:30
Number = 30

In order to accept int input from the user, we have utilized the percent d format specifier inside the scanf() function.

An integer is entered by the user and kept in the testInteger variable.

You can test the above example here! ➡ C Online Compiler

Example 6 of Float and Double Input and Output in C

#include <stdio.h>
int main()
{
    float number1;
    double number2;
    printf("Enter a number: ");
    scanf("%f", &number1);
    printf("Enter another number: ");
    scanf("%lf", &number2);
    printf("number1= %f\n", number1);
    printf("number2= %lf", number2);
    return 0;
}

Output of the above example:

Enter a number:45
Enter another number:69
number1= 45.000000
number2= 69.000000

For float and double, we utilize the percent %f and percent %lf format specifiers, respectively.

You can test the above example here! ➡ C Online Compiler

Example 7 of Character Input and Output in C

#include <stdio.h>
int main()
{
    char character;
    printf("Enter a character: ");
    scanf("%c",&character);     
    printf("You entered %c.", character);  
    return 0;
}   

Output of the above example:

Enter a character: x
You entered x.

The character itself is not kept when a character is typed into the application mentioned above by the user.

An integer value (ASCII value) is instead kept on file.

You can test the above example here! ➡ C Online Compiler

Input and Output Multiple Values in C Program

Here’s how to display multiple user inputs after accepting numerous inputs.

Most of the time, novice programmers are looking for methods to have a function return more than one value.

Unfortunately, C directly prohibits this.

Example 9 of Input and Output Multiple Values in C

#include <stdio.h>
int main()
{
    int x;
    float y;
    printf("Enter integer and then a float: ");
  
    // Taking multiple inputs
    scanf("%d%f", &x, &y);
    printf("You entered %d and %f", x, y);  
    return 0;
}

Output of the above example:

Enter integer and then a float: 45
5.9
You entered 45 and 5.900000

You can test the above example here! ➡ C Online Compiler

Format Specifiers for Input and Output in C

From the above examples, you can see that we use

• %d for int
• %f for float
• %lf for double
• %c for char

This section lists the most popular C data types and the format specifiers used with them.

Summary

In this course, we learned about the C language’s input and output.

We learned how to utilize the printf() and scanf() functions in code to display output to and collect input from users, respectively.

A few other functions for displaying results and accepting user input were also covered.

If you have any questions or suggestions about What is Formatted Input and Output Function in C Language, please feel free to leave a comment below.

About Next Tutorial

In the next following post, I’ll create a File Input and Output in C and try to explain its many components in full detail.

I hope you enjoy this post on What is Formatted Input and Output Function in C Language, in which I attempt to illustrate the language’s core grammar.

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