What is the significance of single quotes vs double quotes in comparisons? [duplicate]

Question

This returns an error:

return (arg[0] == "-" && arg[1] == "-") ? true : false;

error: ISO C++ forbids comparison between pointer and integer

However, this does not:

return (arg[0] == '-' && arg[1] == '-') ? true : false;

What is the difference between ' and " ?

Answer 1

Single-quotes denote a character literal. Double-quotes denote a string literal.

So '-' is of type char¹, whereas "-" is of type const char[2] (which typically decays to const char *).

---

_{1 int in C.}