// Simple cat emulation for a COMP2041/9044 lecture example
// andrewt@unsw.edu.au

#include <stdio.h>
#include <stdlib.h>

// write bytes of stream to stdout
void process_stream(FILE *stream) {
    int byte;
    while ((byte = fgetc(stream)) != EOF) {
        if (fputc(byte, stdout) == EOF) {
            perror("cat:");
            exit(1);
        }
    }
}

// process files given as arguments
// if no arguments process stdin
int main(int argc, char *argv[]) {

    if (argc == 1) {
        process_stream(stdin);
    } else {
        for (int i = 1; i < argc; i++) {
            FILE *in = fopen(argv[i], "r");
            if (in == NULL) {
                fprintf(stderr, "%s: %s: ", argv[0], argv[i]);
                perror("");
                return 1;
            }
            process_stream(in);
            fclose(in);
        }
    }

    return 0;
}