Is -2 > 10 comparing integers

Question

I writing a small program to determine the largest and smallest numbers read from a file. It works fine with all positive integers. However, when it comes to negative integers, things seem broken.

int get_largest(std::ifstream& fin)
{
    int largest, container;
    fin>>container;

    largest = container;

    while (fin>>container)
    {
        if (container>largest)
        {
        //bool check = (container>largest);
        largest = container;
        }
    }

return largest;
}

Here is the main function

#include <iostream>
#include <fstream>

int get_largest(std::ifstream& fin);

int main( int argc, const char * argv[])
{
using namespace std;
ifstream fin("numbers.dat");

 int smallest_value = get_smallest(fin);
 int largest_value = get_largest(fin);

cout<<"The smallest value is "<<smallest_value<<endl;
cout<<"The largest value is "<<largest_value<<endl;


return 0;
}

I pass in a list of numbers in a ifstream like this

The output says the largest number is -2 instead of 10. I tried using signed integers but it does not help.

Thank you for your time!

@Vanna, sure on removing the `check` boolean. But how does outputting help? Thanks! — hacaoideas, Aug 11 '17 at 03:24
@hacaoideas, I don't see any problem in your code! Can you please add the main function code? — kiner_shah, Aug 11 '17 at 03:26
It returned 10 for me. (I changed it to istream so I could pass it a stringstream, for testing, but no other changes). Are you sure it was int? If you had used an unsigned int, then -2 would be much larger than 10. — Kenny Ostrom, Aug 11 '17 at 03:30
@KennyOstrom, very good point....still, I am trying to see how can I properly do the comparison between integers. — hacaoideas, Aug 11 '17 at 03:33
Oh ... you didn't reset the file pointer to the start, after seeing that edit? — Kenny Ostrom, Aug 11 '17 at 03:33
Yep, `get_largest` most likely reads nothing but there's no error checking. — Retired Ninja, Aug 11 '17 at 03:34
@KennyOstrom and Retired Ninja, i am lost here...truly, it works fine with an istring... I did not reset the file pointer...How does it help? — hacaoideas, Aug 11 '17 at 03:43
You read to the end of the file. Trying to read more in the next function just returns an error because you're at the end of the stream. You need to clear the error and seek back to the beginning, or just close and open the file again. — Retired Ninja, Aug 11 '17 at 03:50

Is -2 > 10 comparing integers

0 Answers0