Why a string which contains '\0' and '\t' can't use operator == to compare with "\0\t"?

Question

string s;
s += '\0';
s += '\t';
if (s == "\0\t")
    cout << "Yahoo";

I can't get "yahoo".

And does it mean that if I want to check string like this, I have to code like this?

if (s[0] == '\0' && s[1] == '\t')
    cout << "Yahoo";

Answer 1

You are using the operator which compares a std::string with a const char*. In that function, the const char* is assumed to be pointing to a null-terminated (i.e. '\0') c-string. Since the '\t' comes after the terminator, the function does not consider it as part of the string, and in fact, would have no good way of even being able to figure out that it was there.

You could do this:

if (s == std::string("\0\t",2))

That will construct a std::string with the full string literal (minus the terminating '\0' that the compiler adds), and will compare your string with that.