Purpose of getc and putc Functions in C programming

Purpose of getc and putc Functions in C

The getc and putc functions in C are used for reading and writing single characters from/to a file or stream. They provide a simple and efficient way to handle character-based I/O operations.

getc Function

The getc function is used to read a single character from a file or stream. It returns the next character as an unsigned char cast to an int, or EOF (end-of-file) if the end of the file is reached or an error occurs.

Syntax

int getc(FILE *stream);

Where stream is a pointer to a FILE object that identifies the input stream.

Example Code

#include <stdio.h>

int main() {
    FILE *file = fopen("example.txt", "r");
    int ch;

    if (file != NULL) {
        while ((ch = getc(file)) != EOF) {
            putchar(ch); // Output the character to standard output
        }
        fclose(file); // Close the file
    } else {
        printf("Error opening file.\n");
    }

    return 0;
}

In this example:

• FILE *file = fopen("example.txt", "r"); opens the file example.txt for reading.
• getc(file) reads characters one by one from the file until EOF is reached.
• putchar(ch); outputs each character to the standard output (console).
• fclose(file); closes the file after reading.

putc Function

The putc function is used to write a single character to a file or stream. It returns the character written as an unsigned char cast to an int, or EOF if an error occurs.

Syntax

int putc(int char, FILE *stream);

Where char is the character to be written, and stream is a pointer to a FILE object that identifies the output stream.

Example Code

#include <stdio.h>

int main() {
    FILE *file = fopen("output.txt", "w");

    if (file != NULL) {
        putc('H', file);
        putc('e', file);
        putc('l', file);
        putc('l', file);
        putc('o', file);
        putc('\n', file);

        fclose(file); // Close the file
        printf("Data written to output.txt\n");
    } else {
        printf("Error opening file.\n");
    }

    return 0;
}

In this example:

• FILE *file = fopen("output.txt", "w"); opens the file output.txt for writing.
• putc('H', file); writes the character 'H' to the file.
• Similarly, other characters are written to the file, including a newline character.
• fclose(file); closes the file after writing.

Key Points

• Character-Based I/O: getc and putc are useful for reading and writing individual characters.
• Error Handling: Both functions return EOF to indicate an error or end of file, so always check for this when performing I/O operations.
• File Handling: Ensure the file is successfully opened before using getc or putc, and close the file after operations to free resources.

Note: For more complex I/O operations involving strings or multiple characters, consider using functions like fgets or fprintf.