Capitalize given part of string?

[vboro]

Hi everyone!

I have a program, where I receive a text from the user. In this string, there are parts between quotation marks, as well. My task is to capitalize the part that aren't between the quotation marks, for example:

Input: The "yellow" flower.
Output: THE "yellow" FLOWER.

I was considering the idea of finding the quotation marks of the string and until a quotation mark, I would add (+=) the part of the string, by letters to a result string using toupper() and the part between the quotation marks just simply adding to the string with +=.

What do you think? If you have any suggestions, I'm all ears!!

[lastchance]

(1) Do it as a function
(2) Pass the string by value as an argument and operate on this copy within the function.
(3) Keep a boolean variable (say, inQuotes) to determine whether you are currently within quotes. Initialise it to false and toggle it every time you pass a ". (I guess that makes it a state machine.)
(4) Go through the string character by character and when inQuotes is currently false change any alphabetic character to upper case.
(5) Return the amended string.

I would change an existing string rather than use +=, to avoid continual memory reallocation, especially unnecessary when adding unchanged characters, but that's your choice.

[seeplus]

There are various ways of doing this. The simplest is probably based upon lastchance's method. But the question implies changing the original string? Is this what is wanted - or do you want a new string with the text changed?

As C++20 changing the original string (but its easy to change it into creating a new changed string):

#include <iostream>
#include <string>
#include <cctype>

int main()
{
	std::string str {R"(The "yellow" flower.)"};

	for (bool qte {}; auto& ch : str)
		if (qte = ch == '\"' ? !qte : qte; !qte)
			ch = static_cast<char>(std::toupper(static_cast<unsigned char>(ch)));

	std::cout << str << '\n';
}

THE "yellow" FLOWER.

[vboro]

Thanks everyone a ton for the answers, it worked perfectly!! :D

[lastchance]

#include <iostream>
#include <string>
#include <cctype>
using namespace std;

string filter ( string s )
{
   bool inQuotes = false;
   for ( char &c : s )
   {
      if ( c == '\"' ) inQuotes = !inQuotes;
      if ( !inQuotes && isalpha( c ) ) c = toupper( c );
   }
   return s;
}

int main()
{
   cout << filter( R"(The "yellow" flower.)" ) << '\n';     // Raw string
   cout << filter( "The \"yellow\" flower."  ) << '\n';     // Without raw string
}

THE "yellow" FLOWER.
THE "yellow" FLOWER.