C Library - fputs() function

---

---

The C library int fputs(const char *str, FILE *stream) function writes a string to the specified stream up to but not including the null character.It is commonly used for writing text to files.

Syntax

Following is the C library syntax of the fputs() function −

int fputs(const char *str, FILE *stream);

Parameters

This function accept two parameters −

• const char *str: This is a pointer to the null-terminated string that is to be written to the file.
• FILE *stream: This is a pointer to a FILE object that identifies the stream where the string is to be written. The stream can be an open file or any other standard input/output stream.

Return value

On success, fputs returns a non-negative value. On error, it returns EOF (-1), and the error indicator for the stream is set.

Example 1: Writing a String to a File

This example writes a simple string to a text file.

Below is the illustration of C library fputs() function.

#include <stdio.h>

int main() {
    FILE *file = fopen("example1.txt", "w");
    if (file == NULL) {
        perror("Failed to open file");
        return 1;
    }
    
    if (fputs("Hello, World!\n", file) == EOF) {
        perror("Failed to write to file");
        fclose(file);
        return 1;
    }
    
    fclose(file);
    return 0;
}

Output

The above code opens a file named example1.txt for writing, writes "Hello, World!" to it, and then closes the file. −

Hello, World!

Example 2: Writing Multiple Lines to a File

This example writes multiple lines to a file using fputs in a loop.

#include <stdio.h>

int main() {
    FILE *file = fopen("example3.txt", "w");
    if (file == NULL) {
        perror("Failed to open file");
        return 1;
    }
    
    const char *lines[] = {
        "First line\n",
        "Second line\n",
        "Third line\n"
    };
    
    for (int i = 0; i < 3; ++i) {
        if (fputs(lines[i], file) == EOF) {
            perror("Failed to write to file");
            fclose(file);
            return 1;
        }
    }
    
    fclose(file);
    return 0;
}

Output

After execution of above code,it writes three different lines to example3.txt by iterating through an array of strings and using fputs in each iteration.

First line
Second line
Third line