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