Simple C++ code (what's wrong here?)

Question

Noob to C++.

I'm trying to get user input (Last Name, First Name Middle Name), change part of it (Middle Name to Middle Initial) and then rearrange it (First Middle Initial Last).

Where am I messing up in my code?

--Thanks for ANY help you can offer!

...

#include <iostream>
using std::cout;
using std::cin;

#include <string>
using std::string;

int main()
{

  string myString, last, first, middle;

  cout << "Enter your name: Last, First Middle";

  cin >> last >> first >> middle;

  char comma, space1, space2;

  comma = myString.find_first_of(',');
  space1 = myString.find_first_of(' ');
  space2 = myString.find_last_of(' ');

  last = myString.substr (0, comma); // user input last name
  first = myString.substr (space1+1, -1); // user input first name
  middle = myString.substr (space2+1, -1); // user input middle name

  middle.insert (0, space2+1); // inserts middle initial in front of middle name
  middle.erase (1, -1); // deletes full middle name, leaving only middle initial

  myString = first + ' ' + middle + ' ' + last; //  

  return 0;
}

Answer 1

shouldn't this line :

cin >> last >> first >> middle;

be

cin >> myString;

?

Because after that you search for the comma and spaces in myString but this string contains nothing.

Answer 2

Well you search for things in myString but never set it to anything (it's an empty string).

You should read one whole line into myString.

std::getline(std::cin, myString);

Then you can look out for the , and spaces etc. The second problem is that you should use size_t as the type of comma, space1 and space2. These keep the positions of the spaces and commas in the string: If the comma or space isn't found in input, then the find functions return string::npos, which is the highest value in a size_t. But this would overflow a char. For reliably assigning the position, you should thus change the type of these three variables to size_t.

Then instead of using -1 to say that you want to extract a substring until end just omit it: It has a default argument for that parameter which specifies string::npos. If you really want to pass it, maybe because it improves readability for you, use string::npos instead: It has the right type (size_t), and won't need a conversion of int (with value -1) to it.