Pointers and Strings C++

Question

I\'m teaching myself C++ and I\'m a bit confused about pointers (specifically in the following source code). But first, I proceed with showing you what I know (and then cont

Answer 1

So like string testing = "Hello world"; Is actually a pointer pointing to the memory location where "H" is stored?

No, above you are have object called string. It would be true for char* testing = "Hello World". As you can see it is even declared as pointer and it points to first character in string - H.

Next, why is it in the print out statement that CopyOfName is not *CopyOfName? Pointers hold memory addresses? Using *CopyOfName would print out the contents of the memory location. I tried this in code blocks and if the input text was "Hello World." Using *CopyOfName in the print out statement would just give an "H"

cout take pointer to first character of the string so CopyOfName is right. In this case it will print every character starting from H until it finds \0 (null character). Strings like "hello" have actually 6 characters - 'h' 'e' 'l' 'l' 'o' '\0' When you write *CopyOfName you are dereferencing this pointer and *CopyOfName is actually only one character

Answer 2

I think what you are doing, and others please correct me if I'm wrong, is that you're copying your string into a dynamic char array. So no you are not copying it into a pointer. The reason a pointer is involved there is because dynamic arrays require pointers to allocate their memory correctly if I am right.

Answer 3

It seems like you understand what C-style strings are, but to summarize, they are just arrays of characters in memory, by convention terminated by a nul character \0. Usually they are referenced via a char* pointing to the first letter in the string. When they are printed, typically the characters of the string are printed starting from the first, and printing (or copying, etc.) stops when the \0 terminator is reached.

An std::string is a class that (typically) wraps a C-style string. This means that a std::string object (typically) has a private C-style string that is used to implement its functionality. The function std::string::c_str() returns a pointer to this underlying C-style string.

Let's suppose that char *str; points to a C-style string. If you attempt to run cout << *str << endl;, you noticed that only the first character is printed. That is because of C++'s function overloading. The data type of *str is char, so the char version of cout is called and faithfully prints the single character *str. For compatibility with C-style strings, the version of cout that takes a char* as an argument treats the pointer as a C-style string for printing purposes. If you cout an int*, for example, the underlying int will not be printed.

Edit: Another comment:

The reason that your attempt to dereference an std::string object failed is that, indeed, it is not a pointer. You could dereference the return value of std::string::c_str(), and you would get back the first char of the string.

Related: How is std::string implemented?.