stream problem
 

Hello,

I'm wondering why this outputs garbage:

std::ofstream outFile("test.txt");

outFile << 1.0f << std::endl;
outFile << filename << std::endl;
outFile << 2.0f << std::endl;
std::string s;
float x;
std::ifstream inFile("test.txt");
inFile >> x;
std::cout << x << std::endl;
std::getline(inFile, s, '\n');
std::cout << s << std::endl;
inFile >> x;
std::cout << x << std::endl;

and why this works:

outFile << filename << std::endl;
outFile << 1.0f << std::endl;
outFile << 2.0f << std::endl;
std::string s;
float x;
std::ifstream inFile("test.txt");
std::getline(inFile, s, '\n');
std::cout << s << std::endl;
inFile >> x;
std::cout << x << std::endl;
inFile >> x;
std::cout << x << std::endl;

I think the former doesn't work because the getline() is reading the same
line as the previous inFile >> read. How can I get it to skip to the next
line, if that is indeed the problem.

Re: stream problem
 

"vsgdp" <nospam@nospam.com> wrote in message
news:LMr2b.10463$Qy4.4180@fed1read05...
> Hello,
>
> I'm wondering why this outputs garbage:
>
> std::ofstream outFile("test.txt");
>
> outFile << 1.0f << std::endl;
> outFile << filename << std::endl;
> outFile << 2.0f << std::endl;
> std::string s;
> float x;
> std::ifstream inFile("test.txt");
> inFile >> x;
> std::cout << x << std::endl;
> std::getline(inFile, s, '\n');
> std::cout << s << std::endl;
> inFile >> x;
> std::cout << x << std::endl;
>
> and why this works:
>
> outFile << filename << std::endl;
> outFile << 1.0f << std::endl;
> outFile << 2.0f << std::endl;
> std::string s;
> float x;
> std::ifstream inFile("test.txt");
> std::getline(inFile, s, '\n');
> std::cout << s << std::endl;
> inFile >> x;
> std::cout << x << std::endl;
> inFile >> x;
> std::cout << x << std::endl;
>
> I think the former doesn't work because the getline() is reading the same
> line as the previous inFile >> read.

Not quite.

getline is doing what it is supposed to which is reading up to the next
newline. Your mistake is thinking that inFile >> x will read a newline, but
it doesn't. inFile >> x reads a number and a newline is not part of a
number. So when you have a number followed by a newline the newline is left
behind unread. Then getline comes along and reads it.

> How can I get it to skip to the next
> line, if that is indeed the problem.
>

Use getline twice?

john

Re: stream problem
 

"John Harrison" <john_andronicus@hotmail.com> wrote in message news:bidnc9$87l3m$1@ID-196037.news.uni-
> > How can I get it to skip to the next
> > line, if that is indeed the problem.
> >
>
> Use getline twice?
>
or ignore.