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Aug 24th, 2009

file operation

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Hi all,
I am having problem about file operations. There are a few numbers in my txt file. I want the program to calculate average of these numbers in the txt file. The code I have written is as below. Number of numbers in the file is 5. When I return count it returns 5 .The sum of numbers should be 92 but I get 94, and I get average 18.8 but the correct average should be 18,4 (txt file is attached). So can anyone help me about it? Do you think is it a good idea to calculate it in this way?
Thanks

the code:

C++ Syntax (Toggle Plain Text)
int main()
{
	ifstream fin;	
	fin.open("numbers.txt");
	if (fin.fail())
	{
		cout << "erorr on opening the file \n";
		exit (1);
	}
	cout << "the caculated average is  " << avg_file(fin) << endl;	
	double calculated_avg = avg_file(fin);	
}
double avg_file(ifstream& source_file)
{
	double number_in_file;
	double total = 0;
	int count = 0;
	source_file >> number_in_file;
	while (! source_file.eof())
	{		
		source_file >> number_in_file;
		total = number_in_file + total;
		count ++;
	}	
	//average of numbers in file
	return (count);	
}
int main()
{
	ifstream fin;	
	fin.open("numbers.txt");
	if (fin.fail())
	{
		cout << "erorr on opening the file \n";
		exit (1);
	}
	cout << "the caculated average is  " << avg_file(fin) << endl;	
	double calculated_avg = avg_file(fin);	
}
double avg_file(ifstream& source_file)
{
	double number_in_file;
	double total = 0;
	int count = 0;
	source_file >> number_in_file;
	while (! source_file.eof())
	{		
		source_file >> number_in_file;
		total = number_in_file + total;
		count ++;
	}	
	//average of numbers in file
	return (count);	
}

Attached Files

numbers.txt (47 Bytes, 22 views)

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esesili

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Aug 24th, 2009

Re: file operation

(Toggle Plain Text)

double avg_file(ifstream& source_file)
{
	double number_in_file;
	double total = 0;
	int count = 0;
	while (source_file >> number_in_file)
	{		
		total = number_in_file + total;
		count ++;
	}	
	//average of numbers in file
	return (count);	
}

http://www.daniweb.com/forums/post15...tml#post155265

Last edited by Dave Sinkula; Aug 24th, 2009 at 5:57 pm.

Dave Sinkula

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long time no c

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since Apr 2004

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Aug 24th, 2009

Re: file operation

Two things:
First, you forgot to add the first number to the total.
Second, with while(!source_file.eof()) you run through the last line twice.

Therefore, instead of
10+20+40+10+12 = 92
you get
20+40+10+12+12 = 94

unbeatable0

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Junior Poster in Training

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Aug 24th, 2009

Re: file operation

Thanks for helps. Can you tell me how can I fix it?

esesili

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Aug 24th, 2009

Re: file operation

Click to Expand / Collapse Quote originally posted by esesili ...

Thanks for helps. Can you tell me how can I fix it?

Click to Expand / Collapse Quote originally posted by Dave Sinkula ...

(Toggle Plain Text)
double avg_file(ifstream& source_file)
{
	double number_in_file;
	double total = 0;
	int count = 0;
	while (source_file >> number_in_file)
	{		
		total = number_in_file + total;
		count ++;
	}	
	//average of numbers in file
	return (count);	
}
double avg_file(ifstream& source_file) { double number_in_file; double total = 0; int count = 0; while (source_file >> number_in_file) { total = number_in_file + total; count ++; } //average of numbers in file return (count); }
http://www.daniweb.com/forums/post15...tml#post155265

Pay attention.

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