Thursday 15 June 2017

c++ - Why does ofstream give me an echo ie. writes input twice

When I run the following code, and I write for example "Peter" then the result is that I get "PeterPeter" in the file.




Why?



#include "stdafx.h"
#include "iostream"
#include "iomanip"
#include "cstdlib"
#include "fstream"
#include "string"


using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
ofstream File2;
File2.open("File2.dat",ios::out);

string name;
cout<<"Name?"< while(!cin.eof())

{
cin>>name;
File2< }
return 0;
}


When I change the while loop to




while(cin>>name)
{
File2<}


it works. But I don't understand why the first approach does not.



I can't answer my own question (as I don't have enough reputation). Hence I write my Answer here:




Ahhhh!!! Ok Thanks. Now I got it ^^



I have been testing with



    while(!cin.eof())
{
cin>>name;
File2< cout<}



What happens is that when I tip crtl+z he is still in the while loop. The variable name stays unchanged and is added to "File2" in the next line of code.



The following is working:



while(!cin.eof())
{
cin>>name;
if(!cin.eof()){File2<
cout<}

No comments:

Post a Comment

c++ - Does curly brackets matter for empty constructor?

Those brackets declare an empty, inline constructor. In that case, with them, the constructor does exist, it merely does nothing more than t...