System calls

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>

int main() {
    // Open a source file for reading
    int source_fd = open("source.txt", O_RDONLY);
    if (source_fd == -1) {
        perror("Failed to open source.txt");
        exit(1);
    }

    // Create or open a destination file for writing
    int dest_fd = open("destination.txt", O_WRONLY | O_CREAT | O_TRUNC, 0644);
    if (dest_fd == -1) {
        perror("Failed to open destination.txt");
        close(source_fd);
        exit(1);
    }

    // Read from the source file and write to the destination file
    char buffer[1024];
    ssize_t nread;
    while ((nread = read(source_fd, buffer, sizeof(buffer))) > 0) {
        if (write(dest_fd, buffer, nread) != nread) {
            perror("Write error");
            close(source_fd);
            close(dest_fd);
            exit(1);
        }
    }

    // Check if there was an error during reading
    if (nread < 0) {
        perror("Read error");
    }

    // Close both files
    close(source_fd);
    close(dest_fd);

    return 0;
}