Reading Line by Line in C++ for Pairs

Asked Oct 26 '22 at 14:37

Active Oct 26 '22 at 14:47

Viewed 40 times

I have an input file that looks something like this:

 0.1   239.402
 0.4.   32342.34
 0.7   4.924939
 and so on...

I am trying to read it line by line using the fstream extraction operator >> I need a way to set a while loop condition that would stop at the end of the file, and I need a way to push the two as a pair onto two stacks The stacks are previously implemented in a class file Stack as linked lists I currently have something like

double a, double b
std::string t;
Stack av;
Stack bv;
while(i>>a>>t>>b&&(t=="\t"){
   av.push(a);
   bv.push(b);
}

i know i'm incorrect as it's not always a tab space gap. also the file starts with a couple of spaces until the first row and then has a random number of spaces until the second row, and then a next line. Is there a way to write a program where it knows when there is a double to read and use the random number of whitespaces as separation between a and b?

I hope this makes sense! Thanks so much for your help as I'm a beginner.

edited Oct 26 '22 at 14:43

asked Oct 26 '22 at 14:37

Nathaniel

Provide a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example). – Jason Oct 26 '22 at 14:39
@JasonLiam i just did – Nathaniel Oct 26 '22 at 14:44
`operator >>` for `std::istream` ignores all whitespace by default. All you need is `i >> a >> b` (assuming the file is indeed exactly as you described and you trust it). – Yksisarvinen Oct 26 '22 at 14:45
1

is the 2nd line extra dot in the file, or is that a typeo? – Botond Horváth Oct 26 '22 at 14:47
1

@Yksisarvinen: You meant `i >> a >> b`, didn't you ;-) ? – Serge Ballesta Oct 26 '22 at 14:48
@SergeBallesta Indeed! Was too quick to copy ;) – Yksisarvinen Oct 26 '22 at 14:48
@Nathaniel See [working demo](https://onlinegdb.com/-ds502JIik). – Jason Oct 26 '22 at 14:56

Reading Line by Line in C++ for Pairs

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