Question

The two overloaded function in std::string got my attention:

string& append(const string& str, size_t pos, size_t n);
string& append(const char* s, size_t n);

I’m curious that why the char* version of string::append() doesn’t provide an additional parameter size_t pos, as the one below:

string& append(const char* s, size_t pos, size_t n);

For the other two functions, the situation is also the same:

int compare(size_t pos1, size_t n1, const string& str, size_t pos2, size_t n2) const;
int compare(size_t pos1, size_t n1, const char* s, size_t n2) const;

string& replace(size_t pos1, size_t n1, const string& str, size_t pos2, size_t n2);
string& replace(size_t pos1, size_t n1, const char* s, size_t n2);

The char* version of these functions lack the parameter size_t pos2, which is not as flexible as their string& counterpart. My question is the following:

1. Why does std::string design its interface like this?
2. Why doesn’t the char* version function has size_t pos as well?
3. What’s the consideration(s) behind this?

Thank you for reading!

Answer 1

Because you can just add pos to s:

str.append(ptr + pos, len);

That isn’t to say it wouldn’t be a nice shorthand to have, but they (generally) only want to minimally add the necessary functions, not the trivial wrapper kind.