Input and Output functions in C
What is input in C?
In C, input is any data or information that is provided to a program during runtime. The input can be given by the user or by other programs, and it is used by the program to perform certain operations or calculations.
In C, input can be obtained using various functions such as scanf, getchar, gets, and fgets. These functions allow the program to read input from the user via the keyboard or from other sources such as files.
How to take input in C?
In C, you can take input from the user using various input functions such as scanf, getchar, gets, and fgets.
The scanf function is one of the most commonly used input functions in C. It reads input from the standard input stream, which is usually the keyboard, and stores the values in the specified variables.
Here is an example of how to use the scanf function to read an integer from the user:
Example:
#include <stdio.h>
int main() {
int num;
printf("Enter a number: ");
scanf("%d", &num);
printf("You entered %d\n", num);
return 0;
}
Output:
Enter a number: 12
You entered 12
Explanation:
In this example, the program prompts the user to enter a number, reads the input using the scanf function, and then displays the input using the printf function.
The & symbol before the variable name is used to pass the address of the variable to the scanf function. This is necessary because the scanf function needs to modify the variable directly, and not just create a local copy.
You can use the scanf function to read other data types as well, such as floating-point numbers, characters, and strings. The format specifiers used with the scanf function are:
• %d for integers
• %f for floating-point numbers
• %c for characters
• %s for strings
It is important to note that the scanf function can be prone to errors and unexpected behaviour if not used carefully. It is always a good practice to validate the input and handle any errors that may occur.
What is output in C?
In C, output refers to the data or information that a program displays or writes to the console or other output devices during runtime. The output can be generated by the program itself or obtained from external sources such as files or other programs.
C provides various functions for generating output, including printf, puts, fputs, and fprintf. These functions allow the program to write data to the standard output stream, which is usually the console or terminal, or to other output devices such as files.
How to display output in C?
In C, you can display output on the console or other output devices using various output functions such as printf, puts, fputs, and fprintf.
The printf function is one of the most commonly used output functions in C. It displays output on the console or terminal.
Here's an example of how to use the printf function to display a string on the console:
Example:
#include <stdio.h>
int main() {
printf("Hello, world!\n");
return 0;
}
Output:
Hello, world!
In this example, the printf function is used to display the string "Hello, world!" on the console. The \n character is used to insert a new line after the string, which causes the next line of output to appear on a new line.
You can use the printf function to display other data types as well, such as integers, floating-point numbers, characters, and strings. The format specifiers used with the printf function are:
• %d for integers
• %f for floating-point numbers
• %c for characters
• %s for strings
Here's an example of how to use the printf function to display an integer:
Example:
#include <stdio.h>
int main() {
int num = 10;
printf("The number is %d\n", num);
return 0;
}
Output:
The number is 10
In this example, the printf function is used to display the value of the num variable, which is an integer. The %d format specifier is used to tell printf to display the value of the integer.
It is important to note that you should always validate the output and handle any errors that may occur. It is also a good practice to use appropriate formatting and ensure that the output is clear and easy to read.