help with flow control using files

[maddimarrone]

For my lab, the user is supposed to input a filename. That file prints out the date and price and then my code is supposed to find the highest and lowest prices and print those out with their corresponding dates. I feel like the logic in my code makes sense but it's not working.

Here is my code:

#include <iostream>
#include <limits>
#include <fstream>
#include <string>

using namespace std;

//Todo: declare your functions here.
int main()
{
ifstream infile;
string fileName;
cout <<"Enter the name of the file to be analyzed:";
cin >> fileName;

// TODO: Open the filename and test that it was successful
infile.open(fileName);

// Used to read in the date, price and the rest.
double price = 0;
string date, junk;
// Going to store the date of the high price and low price
string lowDate, highDate;

// Going to store the high price and low price.
double high = -9999999;
double low = 99999;


cout.precision(2);
cout.setf(ios::fixed);

if(infile.is_open() == false)// problem opening the file? Maybe it does not exist
cout << "File " << fileName << " cannot be opened.";

// TODO: Implement a loop that reads line by line from input.
// TODO: A line has the date, the price and the rest (use junk)
// TODO: Stop reading on end of input.

while ( infile >> date >> price >> junk ) // treat infile like 'cin'
{
cout << date << " " << price << endl;

// TODO: Find the highest price
// TODO: Save the date of the price
// TODO: Find the lowest price
// TODO: Save the date of the price

if (price > high)
{
price = high;
date = highDate;
}
else if (price < low)
{
price = low;
date = lowDate;
break;
}

cout << "High: " << high << " on " << highDate << endl;
cout << "Low: " << low << " on " << lowDate << endl;
}


infile.close();
}

P.S. I know the last two cout statements to print the highest and lowest prices should be outside of the while loop, but when I do that it still outputs the statements if the file fails to open which is not what's supposed to happen so I also don't know what to do about that.

[coder777]

I feel like the logic in my code makes sense but it's not working.

Well, it does not work hence it is actually wrong. You have it reverse, try this:

while ( infile >> date >> price >> junk ) // treat infile like 'cin'
{
cout << date << " " << price << endl;

// TODO: Find the highest price
// TODO: Save the date of the price
// TODO: Find the lowest price
// TODO: Save the date of the price

if (price > high)
{
high = price; // price = high;
highDate = date; // date = highDate;
}
else if (price < low)
{
low = price; // price = low;
lowDate = date; // date = lowDate;
// break;
}

}

cout << "High: " << high << " on " << highDate << endl;
cout << "Low: " << low << " on " << lowDate << endl;

[maddimarrone]

Thank you that helped! Now, my only issue is the cout statement when the file fails to open. I want it to just execute this part:

if(infile.is_open() == false)// problem opening the file? Maybe it does not exist
cout << "File " << fileName << " cannot be opened.";

How do I make it so it doesn't also output the:

cout << "High: " << high << " on " << highDate << endl;
cout << "Low: " << low << " on " << lowDate << endl;

[Handy Andy]

Hello maddimarrone,

// TODO: Open the filename and test that it was successful
infile.open(fileName);

So where is your test? If the file did not open you still continue with the program.

Found the test at line 24, but it is to late and the program still continues if the file did not open

Try this:

int main()
{
	ifstream infile;
	string fileName;

	cout << "Enter the name of the file to be analyzed:";
	std::getline(std::cin, fileName); // <--- Because the file name may contain a space.

	// TODO: Open the filename and test that it was successful
	infile.open(fileName);

	ifI(!infile)
	{
		std::cout << "\n    File \"" << fileName << "\" did not open!\n";

		return 1;  // <--- Leave the program because there is no point in continuing.
	}

With out seeing the input file, or a fair sample, it is hard to say if you are reading the file correctly to start with.

Andy

[Handy Andy]

Hello maddimarrone,

Forgot to mention:

PLEASE ALWAYS USE CODE TAGS (the <> formatting button), to the right of this box, when posting code.

Along with the proper indenting it makes it easier to read your code and also easier to respond to your post.

http://www.cplusplus.com/articles/jEywvCM9/
http://www.cplusplus.com/articles/z13hAqkS/

Hint: You can edit your post, highlight your code and press the <> formatting button.

You can use the preview button at the bottom to see how it looks.

I found the second link to be the most help.

Andy