C code to print the size of file(s) in a human friendly format

size.c

#include <stdio.h>
#include <ftw.h>
#include <sys/stat.h>
#include <sys/dir.h>
#include <dirent.h>

void printbytes(char *filename, long l)
{
    printf("%s: ", filename);

    if (l < 1000)
    {
        printf("%ld bytes\n", l);
        return;
    }
    if (l < 1000000)
    {
        printf("%f KB\n", l / 1000.0);
        return;
    }
    if (l < 1000000000)
    {
        printf("%f MB\n", l / 1000000.0);
        return;
    }
    if (l < 1000000000000)
    {
        printf("%f GB", l / 1000000000.0);
        return;
    }
    if (l < 1000000000000000)
    {
        printf("%f TB", l / 1000000000000.0);
        return;
    }
    printf("%f PB", l / 1000000000000000.0);

    printf("\n");
}

long getfilesize(char *path)
{
    FILE *fp = fopen(path, "r");
    if (!fp)
    {
        return -1;
    }
    fseek(fp, 0, SEEK_END);
    long s = ftell(fp);
    fclose(fp);
    return s;
}

int main(int argc, char *argv[])
{
    long total = 0;
    if (argc == 1)
    {
        printf("Usage: %s [file1] [file2] [file3] ...\n", argv[0]);
        return 1;
    }
    for (int i = 1; i < argc; i++)
    {
        char *path = argv[i];
        struct stat st;
        if (stat(path, &st) != 0)
        {
            fprintf(stderr, "Could not open %s, skipping...\n", path);
            continue;
        }

        if (S_ISDIR(st.st_mode))
        {
            fprintf(stderr, "%s is a directory.\nTo get the size of a directory, please use wildcards.\n", path);
            continue;
        }

        long size = getfilesize(path);
        if (size == -1)
        {
            fprintf(stderr, "Could not open %s, skipping...\n", path);
            continue;
        }
        printbytes(path, size);
        total += size;
    }
    if(argc > 2) {
        printbytes("\033[0;34mTotal", total);
        printf("\033[0m");
    }
    return 0;
}