How to display characters in a write() funtion C

February 14, 2024

I’m trying to display a certain way of outputting information. Right now I’m using Vim in the shell of Linux

to display a ‘char’ written in a function
it has to be portrayed like this

void ft_putchar(char c);

AND it has to be displayed via another function like so

write(1, &c, 1);

Right now I have no idea what I’m doing wrong, but I have many error codes.

I tried putting both functions into the main() one but the only thing I receive while trying to compile are errors.
this is my code:

#include <unistd.h>
#include <stdio.h>

void ft_putchar(char c);
{
        write(1, &c , 1)
}

int main(){
        ft_putchar('a');
}

and this is the error code –

└─$ gcc ft_putchar.c
ft_putchar.c:5:1: error: expected identifier or ‘(’ before ‘{’ token
5 | {
| ^

>Solution :

Firstly, ensure you have included the necessary header for the write function. The write function is defined in unistd.h, so you need to include this header at the top of your file.

Here’s a simple example of how you might define ft_putchar and use it in a main function:

#include <unistd.h>

// Function declaration
void ft_putchar(char c);

int main() {
    // Example usage of ft_putchar
    ft_putchar('H');
    ft_putchar('e');
    ft_putchar('l');
    ft_putchar('l');
    ft_putchar('o');
    ft_putchar('\n');

    return 0;
}

// Function definition
void ft_putchar(char c) {
    write(1, &c, 1);
}

In this example:
The ft_putchar function takes a single character c as its parameter.
It then calls write, with 1 as the first argument to specify the file descriptor for standard output (stdout), &c to pass the address of the character to write (since write expects a pointer), and 1 as the third argument to specify that
we want to write one byte (since a char in C is typically one byte).