Thread: Questions on std::string

I have two questions on std::strings, first of all, is there anyway to get the soucecode for string.cpp (or wherever the class is implemented)? Or, is there a way to get a complete list of member functions in std::string?

My second question is more complicated. I am trying to write a few functions that I didn't find in the partial list of std::string member functions that I've been looking at. I want my functions to take a reference to a string and operate on it, thereby not needing a return value and I can't seem to get it to work.

Here is an example of one of the functions that I'm writing:

Code:

void StringToUpperCase(string* pString)
{
	for (int x = 0; x < *pString->length(); x++)
	{
		if ((((int)*pString[x] < 64) || ((int)*pString[x] > 122)) || (((int)*pString[x] >= 65) && ((int)*pString[x] <= 90))) {}
		
		*pString[x] -= 32; 
	}
}

The function is being called like:

Code:

string p = "ilikestring";
StringToUpperCase(&p);

Now, it's entirely possible that i'm doing something really stupid, but I don't think I am, I think that there is some sort of different way to dereference strings (or maybe it's because it's a class) can anyone tell me how I can do this? It probably is something stupid, I heaven't touched a compiler in a long time...

I've found this to be a good reference for most of the c++ standard libray http://www.dinkumware.com/refxcpp.html


For your code you have to dereference the pointer before using the array operator like this:

Code:

(*pString)[x]

Hehe, thank you Sigfried, I tried to dereference but I didn't realize that I needed parenthesis(sp). Thanks again.

Or, is there a way to get a complete list of member functions in std::string?

http://www.cppreference.com/cppstring.html
Though that list seems to be missing the operator functions

As for your function, why are you passing it as a pointer?

Code:

#include <cstring>
#include <string>
void StringToUpperCase(std::string &s)
{
  for (int i=0; i < s.length() i++)
    s[i] = toupper(s[i]);
}

As a note you should never use the integer values when testing for characters. It is much better to use the character literals ('a', 'z', 'A', 'Z', etc)

Hmmmph. I didn't realize that you could just declare in a function header that you only want a reference to a variable, I thought you had to declare it a pointer, pass in a reference, and dereference it in the function, thanks for pointing that out to me Thantos!

As for your remark about not using numerals...why not? ASCII is standard isn't it?

I have a different question about std::string now. Is it possible to make an array of dynamic size full of std::strings?

ok, well how can I make a vector of strings? Can you give me a line of code that will do it?

well a vector of 5 ints would look like:

Code:

std::vector<int> vInts(5)

I'm trying to create a vector of strings that is uninitialized with a variable size, when I use your method Thantos, but replacing int with string, I get a bunch of wierd errors (i'm using VC++ 6.0)

Prelude, what is the const_iterator in your example, do I need it to create a vector of strings? What does it do?