Hmm... I don't see a function in std::string with a signature like:
```
string& replace ( iterator i1, iterator i2, const char* s, const char* t );
```

Also, the documentation states that "For the versions with iterators _i1_ and _i2_, the section replaced is the one formed by the elements between iterator i1 and the element right before iterator i2." [1]

I'm sure there's a way to do this with iterators. But I'm not smart enough to figure out what it is. :-)

[1] http://www.cplusplus.com/reference/string/string/replace/