How to make Value Returning function

[Reynolds773]

I keep getting an error that says "lowest is being used without being initialized". I understand what it means. The lowest variable has no value in the GetLeast function and is trying to be used there. Where do I define it?

#include<iostream>
#include<fstream>
#include<string>
using namespace std;

/*	TODO:	Modify as necessary to be a value returning function
			instead of a void function.
*/

int GetLeast();

//------------------------------------------------------------------------------

int main()
{
	int smallestValue = INT_MAX;		// Initialize smallest to maximum range
	ifstream dataFile;									// File input stream
	const string filename = "data.txt";					// Input file name

	cout << "Opening file...";

	dataFile.open(filename.c_str());					// Open file

	if(dataFile)										// File opened OK?
	{
		cout << "file opened." << endl
			 << "Begin searching for lowest value...";

		/*	TODO:	Modify as necessary for a value returning function.
		*/

		smallestValue = GetLeast();


		cout << "done.\n" << endl;						// Print result

		cout << "The lowest value found was " 
			 << smallestValue << endl;
	}
	else												// Problem opening file
	{
		cout << "could not find or open file: " << filename 
			 << endl;
	}

	dataFile.close();

	cout << "\nEnd Program.\n"
		 << endl;

	return 0;
}

//------------------------------------------------------------------------------

/*	TODO:	Modify as necessary for a value returning function
			instead of a void function.
*/

int GetLeast()
{
	ifstream infile;
	int lowest;
	int value;
	infile >> value;			// Priming read

	while(infile)				// Test for EOF
	{
		if(value < lowest)		// Test for lowest value
			lowest = value;

		infile >> value;		// Read next value
	}
	return lowest;
}

[scapegote]

The issue is because of line 69.

if(value < lowest)

You are trying to test value against lowest without assigning lowest a value. The way I would fix it is add

lowest = value;

below line 65, basically setting the first "value" as the initial lowest.

[Reynolds773]

Okay, I understand what you are saying. I used the debugger and at line 65 the value is reading "value = -858993460" which isn't right, because the first value in the file is 10. Did I declare the wrong ifstream??

This is the code with your added suggestion:

#include<iostream>
#include<fstream>
#include<string>
using namespace std;

/*	TODO:	Modify as necessary to be a value returning function
			instead of a void function.
*/

int GetLeast();

//------------------------------------------------------------------------------

int main()
{
	int smallestValue = INT_MAX;		// Initialize smallest to maximum range
	ifstream dataFile;									// File input stream
	const string filename = "data.txt";					// Input file name

	cout << "Opening file...";

	dataFile.open(filename.c_str());					// Open file

	if(dataFile)										// File opened OK?
	{
		cout << "file opened." << endl
			 << "Begin searching for lowest value...";

		/*	TODO:	Modify as necessary for a value returning function.
		*/

		smallestValue = GetLeast();


		cout << "done.\n" << endl;						// Print result

		cout << "The lowest value found was " 
			 << smallestValue << endl;
	}
	else												// Problem opening file
	{
		cout << "could not find or open file: " << filename 
			 << endl;
	}

	dataFile.close();

	cout << "\nEnd Program.\n"
		 << endl;

	return 0;
}

//------------------------------------------------------------------------------

/*	TODO:	Modify as necessary for a value returning function
			instead of a void function.
*/

int GetLeast()
{
	ifstream infile;
	int lowest;
	int value;
	infile >> value;			// Priming read
	lowest = value;

	while(infile)				// Test for EOF
	{
		if(value < lowest)		// Test for lowest value
			lowest = value;

		infile >> value;		// Read next value
	}
	return lowest;
}

[Reynolds773]

bump

[Reynolds773]

Still can't figure out why the first value passed in is an absurd number on line 65.

[freddy92]

The function has no idea what file you're talking about. You never open it in GetLeast or pass it in, so it doesn't know. I believe you can pass the dataFile stream to the function, then just use that rather than declaring it inside the function, though I think it has to be passed by reference so look out for that.

[Raezzor]

On line 62 you declared a new ifstream object, but didn't use it to open the file so it's not associated with anything. Not sure if it's even necessary or feasible to declare a 2nd one and associate it with the file you are working with. I would try removing lines 62 and changing lines 65 and 73 to read dataFile >> value.

[Lowest0ne]

dataFile is local to main(), you need to pass it to your function:

void myFunc(ifstream& input)
{
  int ch;
  while ((ch = input.get()) != ios::eof) cout << (char)ch;
}

int main(void)
{
  ifstream myFile("data.txt");
  if (myFile.is_open())  myFunc(myFile);
  return 0;
}

[Reynolds773]

I just figured it out. I never actually opened the file in the function. Just had to add "infile.open("data.txt");" after line 61.

Thanks for the help!