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

int lc(FILE* fp)
{
    char c[1];
    int num_lines = 0;
	  int fn = fileno(fp);
    while (read(fn, c, sizeof(c)) > 0) {
        if (*c == '\n' ) {
					num_lines ++;
        }
    }
    printf("%i\n", num_lines);
    return 0;
}

int main(int argc, char** argv)
{
    if (argc == 1) {
        return lc(stdin);
    } else if (argc > 1) {
        FILE* fp = fopen(argv[1], "r");
        if (!fp) {
            perror("Could not open file");
            return 1;
        }
				return lc(fp) && fclose(fp);
    } else {
        printf("Usage: lc file.txt\n");
        printf("   or: cat file.txt | lc\n");
        printf("   or: lc # read from user-inputted stdin\n");
    }
    return 0;
}