Recursion confusion

[avanhoes]

I'm really stuck on this one:

Write the definition of a function named copy that reads all the strings remaining to be read in standard input and displays them, one on a line with no other spacing, onto standard output .

I know I'm supposed to write a recursive function, but not sure how to do that with cin and cout. I got all the other ones right but this one is stumping me.

[avanhoes]

so far I got

void copy ()
{
	string x;
	cin >> x;
	
	if(cin.fail())
	cout << x <<endl;
	return(copy();
}

[unsensible]

What do you mean by reading "all the string remaining"?

[avanhoes]

I guess it reads in a list of strings and then is supposed to output them all in one line with now spaces. That is just how it's stated, hence my confusion.

[unsensible]

If that's the case then what you have is basically correct

You might want to just add the keyword "else" before return so that the recursion will break when someone enters a value that isn't a string.

Other than that, they will all display on one line continuously because there is no endl or \n, which is what you want.

[avanhoes]

This goes into a infinite loop when I submit it. It a stupid my programming lab assignment and it has to be done their way. I'm assuming I have a line that reads something like this "Here comes the sun". It wants me to read in each word to string x and then output the whole string.

[unsensible]

Gotcha. Yeah I forgot with strings the only real way to make cin.fail return true is if you press Ctrl + z in the console and press enter. That will break the loop.

Is this what you're looking for:

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

string copy (string x)
{
     string word;
	cin>>word;
	x=x+word+" ";

	if(cin.fail()){
	   return x;
	}

	else
	   return(copy(x));
}

int main(){
    string val="";
    cout<<copy(val)<<endl;
    system("pause");

}

[avanhoes]

Mostly.. apparently it is supposed to be void and can't accept any parameter. This is the dumbest assignment ever. How would you just recursively call the cin function?

[unsensible]

Well you basically are already recursively calling the cin function because every time the function is called, you have to cin a value. Are you allowed to use global variables?

[avanhoes]

#include <iostream>
using namespace std;
void copy();

That code is what is within My Programming Lab. Other than the brief sentence in the first post the only thing is says I cannot do is use a loop (obviously... it has to be recursive).

[unsensible]

I'll be honest with you, I don't know how to do it without a parameter or a global variable. Here's how to go about it using globals:

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

string x;
string word;
void copy ()
{
	cin>>x;
     word+=x+" ";
	
	if(cin.fail()){
	   cout<<word<<endl;
	}

	else
	   return(copy());
}

int main(){
  
    copy();
    cout<<endl;
    system("pause");

}

Technically, the program is still void and accepts no parameters so..

[avanhoes]

Still not it... Thank you for your help.

[long double main]

You could try something like this:

#include <iostream>
#include <string>

void copy()
{
    std::string str;
    if (!(std::cin >> str))
        return;
    std::cout << str << '\n';
    copy();
}

int main()
{
    copy();
}

Keep in mind that if the input is coming from the user (the keyboard), then the condition on line 7 will never be satisfied, and it'll just keep on asking for more input.
So I would either get the input from a file instead, or just enter a EOF character (Ctrl+Z on a blank line in Windows; not sure about other OSs) when you're done entering your input.

This shows the former method:
http://coliru.stacked-crooked.com/a/03a0cb2782ef938b