Skip to main content

Getchar and Putchar in C

Getchar and Putchar​

  • getchar() and putchar() are two basic input and output functions in C.

  • These functions are used to read and write data one character at a time, or character by character.

  • Both getchar() and putchar() are part of the stdio.h header file, which is included at the beginning of the program.

Getchar​

  • The getchar() function reads a single character from the console

  • The getchar() function takes no arguments and returns an integer value that represents the character read from the console.

  • If there are no more characters to be read, getchar() returns the special value EOF (End Of File).

Putchar​

  • The putchar() function writes a single character to the console.

  • The putchar() function takes a single integer argument that represents the character to be written to the console.

  • The function returns an integer value that represents the character that was written, or EOF if an error occurred.

The basic syntax and header files for getchar() and putchar() are as follows:

#include <stdio.h>

int getchar(void);
int putchar(int c);

Example​

Here's an example C program that uses getchar() and putchar() functions to read input characters one by one and write them back to the console:

#include <stdio.h>

int main() {
    char c;

    printf("Enter a message: ");

    while ((c = getchar()) != '\n') {
        putchar(c);
    }

    return 0;
}

Explanation:

  • We first declare a character variable c.
  • We then print a message to the console using printf() function, asking the user to enter a message.
  • We then use a while loop to read input characters one by one using the getchar() function.
  • The while loop continues until the getchar() function reads a newline character (\n), which signifies the end of the user's input.
  • Inside the while loop, each input character is immediately printed back to the console using the putchar() function.

When this program is run, the user is prompted to enter a message. As they enter the message, each character is echoed back to the console in real-time. Once they press Enter, the program stops reading input and terminates.

Output:

Enter a message: Hello, World!
Hello, World!

The user entered the message "Hello, World!" and the program echoed the message back to the console.