Question

I was writing a program which could read inputs directly from a text
file into a C++ file. However, the contents of the file come in
different formats, for example time. The input file looks like this:

Time(1) Price(1)
8:56:18 1250.00
9:00:25 1250.25
9:21:36 1250.50
9:23:32 1249.75

Time(2)
8:55:28
9:02:14
9:20:23
9:21:37
Price(2)
1680.50
1681.00
1680.50
1681.50

My program to read the file is as follows:

int main()
{
    string file;
    cout << "Enter a file name to read input: ";
    cin >> file;

    ifstream file_name(file.c_str());

    while(!file_name.eof())
    {
        double input;
        file_name >> input;
        cout << input << endl;
    }
}

But when I executed the program, I get stuck in an infinite loop and
all I see are 0s written on the screen. Is this being caused due the
formatting of the time?

Answer 1

The default behavior of file_name >> input is type safe therefore file_name byte offset pointer never increments for inputs like Time(1) or 8:56:18. You may use string input; instead of double input; to retrieve the values, then later you may check their types by using following standard c library.

#include <cstdlib>
.
.
.
atof()
atoi()
.

Here is the documentation.