using strings in C++ // how do i? - c++

Question

I need help changing my current program so that it displays the letters already entered by the user, and displays the letters again immediately before prompting the user to enter another letter. what I have so far is below.
int main()
{
char another = 'Y';
string message = "";
while (toupper(another) == 'Y')
{
cout << "Enter a message: ";
getline(cin, message);
for (int x = 0; x < message.length(); x += 1)
cout << message.substr(x) << endl;
cout << endl << "Another message (Y/N)? ";
cin >> another;
cin.ignore(100, '\n');
}
system("pause");
return 0;
}

Answer 1

If you want all the characters (you entered at any time) printed, you can do the following:
Start off with two empty strings. One is a buffer, that stores the string that's currently added and the other holds all of the strings already added, like so:
string buf = "";
string messages = "";
Read your characters into your buffer, via:
getline(cin, buf);
Append the string to the other messages, already entered:
messages.append(buf);
Append a string delimiter to your messages, so you know which sequence of characters (including whitespaces) belong to the message you entered:
messages.append(";");
(BTW: Using "-quotes here is really important, to let the compiler know you are comparing strings, not characters, as there is no string::append(char s)-method defined, only string::append(string s).)
Iterate through your messages-string, and check if the character at position x is equal to ';' (Using '-quotes here is also important, because string::operator[] return a character not a string!!!). For instance you might code:
for (int x = 0; x < messages.length(); x++) {
//Test if string delimiter is reached, if so, jump to next line.
if(messages[x] == ';') {
std::cout << "\n";
}
//Else just print the string:
else {
std::cout << messages[x];
}
}
Test if another message should be entered.
OR you create a linked list of strings. Adding new strings to the list, every time you enter a new string. This might be the more elegant way to do this, however it is slightly more involved. (I'm assuming you're fairly new to programming, if not I apologize!). Check Wikipedia or cplusplus.com for more info on linked lists!
Hope I could answer your question,
lindebear