The definition of a line of code, though basic to many software metrics, is ambiguous. What a "line of code" means will certainly vary across languages, but it also varies for a given language.

In the C language, for example, a line of code might be (1) a statement terminated by a newline, (2) a statement terminated by a semicolon, or (3) any line in the program terminated by a newline (comments included).

for (i=0; i<100; ++i) {printf("hello");} /* How many lines of code is this? */