Making your output to look like its being typed!

[Tallrick]

Hello! I'm a student at a game programming course in Sweden and I've recently started to begin learning c++ in my spare time. First post here, so please be gentle. ;)

For now I'm trying to make a simple dialogue game in the console window, and I'm trying to make my output text look as if someone is typing it to you. I've only managed to make words appear one at a time but what I'm trying to do is to make each letter of every word to appear one after the other. My code looks like this:

#include "stdafx.h"
#include "iostream"
#include "cstdlib"
#include "istream"
#include "string"
#include "new"
#include "stdio.h"
#include "sstream"
#include "windows.h"
#include "time.h"


using namespace std;

string stringAnswer;
string yourName;

void game ()
{
	bool donePlaying = false;
	bool nameUnknown = true;

	while (!donePlaying)
	{
	while (nameUnknown == true)
	{
		cout << "Please "; Sleep(100); cout << "enter "; Sleep(100); cout << "your "; Sleep(100); cout << "name. " << endl;
		cout << "I "; Sleep(100); cout << "would "; Sleep(100); cout << "like "; Sleep(100); cout << "to "; Sleep(100);
		cout << "get " ; Sleep(100); cout << "to "; Sleep(100); "to "; Sleep(100); cout << "know "; Sleep(100); cout << "you "; Sleep(100); cout << "better." << endl;
		getline (cin, stringAnswer);
		stringstream(stringAnswer) >> yourName;
		nameUnknown = false;
		Sleep(700);
		cout << "Welcome, ";
		Sleep(400);
		cout << yourName << "." << endl;
	}

	if(GetAsyncKeyState(VK_ESCAPE))
	{
		donePlaying = true;
	}

	}
}

void main ()
{
	game ();
}

Fear not, I AM aware of that this code is extremely silly.

Also, how do I make the text that's been written to be erased?

Thanks in advance!

[Peter87]

#include <iostream>
#include <unistd.h> // include <windows.h> on windows

// function to output as if it was being typed
void type_text(const std::string& text)
{
	// loop through each character in the text
	for (std::size_t i = 0; i < text.size(); ++i)
	{
		// output one character
		// flush to make sure the output is not delayed
		std::cout << text[i] << std::flush;
		
		// sleep 60 milliseconds
		usleep(60000); // use Sleep on windows
	}
}
int main()
{
	type_text("Hej hej hallå!");
}

How to erase text I don't know. It's not possible with standard C++ so you have to use system/library functions for that.

[Tallrick]

Thank you very much! The function type_text works incredibly. I have a few questions though:

I know that this "::" operator, after std refers to a built in class. But what's the purpose of "&" after "string". Is "text" another type just like "string" or are you making "text" a string type? And I've never heard of "std::flush" before, could you clarify what that is?

[Peter87]

Almost everything in the standard library is in the std namespace. That's why I write std:: infront of everything. In your code you wrote using namespace std;, that makes so you don't have to write std::. The & after string means it's a reference to a string. If you don't use a reference it will create a copy of the string which is slower. Inside the function we can use text like a normal string. When writing output the text will not always be updated right away. It might not be visible until a complete line is written. std::flush just makes so that all written output will be visible now and not later.

[Tallrick]

Thanks a lot, it makes total sense. :) But alas from your answer rises a new question. Isn't it always better to include

using namespace std;

? What is the advantage of typing it out except for simple clarification?

[Peter87]

Name clashes are more likely to happen when you use using namespace std;. Here is an example:

#include <algorithm>
using namespace std;

int count;

int main()
{
	count = 23;
}

That code will not compile because the compiler doesn't know if you mean count on line 4 or std::count from the <algorithm> header.

I also think that std:: makes more readable code.

[Tallrick]

Thank you very much. :) You've helped a stumbling newbie!