Double output!

This is a discussion on Double output! within the C++ Programming forums, part of the General Programming Boards category; Ok...can anyone tell me why the while loop outputs the last bit of data twice?? if you can...that'd be cool...thanx ...

  1. #1
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    Nov 2002
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    4

    Question Double output!

    Ok...can anyone tell me why the while loop outputs the last bit of data twice?? if you can...that'd be cool...thanx
    here's the code:

    Code:
    #include<fstream.h>
    #include<iomanip.h>
    
    void main (void)
    
    {
    	ifstream inputfile;
    	ofstream outputfile;
    	int Max, Min;
    	float Avg, Num1, Num2, Num3, Num4, Num5, Num6, Num7;
    	float Total;
    	char Data[8];
    
    	inputfile.open("C:\\Hell\\Input.dat", ios::in);
    	outputfile.open("C:\\Hell\\Output.dat", ios::out);
    	if (!inputfile)
    		cout << "Your file is bad or does not exist. Please try again later.";
    	inputfile >> Data;
    
    	while (!inputfile.eof())
    		{
    			Max = 0;
    			Min = 1000;
    			inputfile >> Num1 >> Num2 >> Num3 >> Num4 >> Num5 >> Num6 >> Num7;
    			if (Num1 > Max)
    				Max = Num1;
    			if (Num2 > Max)
    				Max = Num2;
    			if (Num3 > Max)
    				Max = Num3;
    			if (Num4 > Max)
    				Max = Num4;
    			if (Num5 > Max)
    				Max = Num5;
    			if (Num6 > Max)
    				Max = Num6;
    			if (Num7 > Max)
    				Max = Num7;
    
    			if (Num1 < Min)
    				Min = Num1;
    			if (Num2 < Min)
    				Min = Num2;
    			if (Num3 < Min)
    				Min = Num3;
    			if (Num4 < Min)
    				Min = Num4;
    			if (Num5 < Min)
    				Min = Num5;
    			if (Num6 < Min)
    				Min = Num6;
    			if (Num7 < Min)
    				Min = Num7;
    
    			Total = (Num1 + Num2 + Num3 + Num4 + Num5 + Num6 + Num7);
    			Avg = (Total / 7);
    
    			outputfile << Num1 << " " << Num2 << " " << Num3 << " " << Num4 << " " << Num5 << " " << Num6 << " " << Num7 << " " << endl;
    			outputfile << "The biggest number is:           " << Max << endl;
    			outputfile << "The smallest number is:          " << Min << endl;
    			outputfile << "The total of those numbers is:   " << setiosflags(ios::fixed) << Total << endl;
    			outputfile << "The average of those numbers is: " << setprecision(2) << Avg << endl;
    			outputfile << endl;
    		}
    	inputfile.close();
    	outputfile.close();
    }
    If you can tell me why it's being weird...that'd be cool...oh yeah...here's the data i'm using...lol

    Data
    346 130 982 90 656 117 595
    415 948 126 4 558 571 87
    42 360 412 721 463 47 119
    441 190 985 214 509 2 571
    77 81 681 651 995 93 74
    310 9 995 561 92 14 288
    466 664 892 8 766 34 639
    151 64 98 813 67 834 369

    the output goes ok...but...it does this...

    The biggest number is: 834
    The smallest number is: 64
    The total of those numbers is: 2396
    The average of those numbers is: 342.29

    151 64 98 813 67 834 369
    The biggest number is: 834
    The smallest number is: 64
    The total of those numbers is: 2396
    The average of those numbers is: 342.29

    WHY OH WHY DOES THE LAST ONE COME OUT TWICE! ACK!
    Thanx again :-)
    Last edited by Spurnout; 11-01-2002 at 02:24 PM.

  2. #2
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    Join Date
    Sep 2002
    Posts
    272
    eof isn't set until the end of file is reached. Your code -

    1)Test if eof has been set
    2)Read from file
    3)Set eof if end of file reached (implicit)
    4)Loop

    Therefore, before eof is set you've already read an entry.

    file a:
    a

    first iteration -

    1)test if eof has been set
    No

    2)Read from file
    'a'

    3)Set eof if end of file reached (implicit)
    No 'a' was read.

    4)Loop -

    second iteration

    1)test if eof has been set
    No

    2)Read from file
    eof is reached (but not set yet), but file read anyway
    'a'

    3)Set eof if end of file reached (implicit)
    Yes

    4)Loop -

    stop.

    You have to test for eof after an attempted read not before one.
    Joe

  3. #3
    I lurk
    Join Date
    Aug 2002
    Posts
    1,361
    Code:
    #include <fstream>
    #include <iostream>
    #include <iomanip>
    
    
    int main(int argc, char *argv[])
    {
    	using namespace std;
    	ifstream inputfile("C:\\Hell\\Input.dat");
    	ofstream outputfile("C:\\Hell\\Output.dat");
    
    	int Max, Min;
    	float Avg, Total = 0;
    	float numbers[7];
    
    	char Data[8];
    
    	if (inputfile.fail())
    	{
    		cout << "Your file is bad or does not exist. Please try again later.";
    		return 0;
    	}
    	inputfile >> Data;
    
    	while (!inputfile.eof())
    	{
    		Max = 0;
    		Min = 1000;
    		for (int i = 0; i < 7; i++)
    		{
    			inputfile >> numbers[i];
    			if (inputfile.eof())
    				break;
    
    			if (numbers[i] > Max)
    				Max = numbers[i];
    			else if (numbers[i] < Min)
    				Min = numbers[i];
    
    			Total += numbers[i];
    		}
    		Avg = (Total / i+1);
    
    		for (i = 0; i < 7; i++)
    			outputfile << numbers[i] << " ";
    
    		outputfile << endl;
    
    		outputfile << "The biggest number is:           " << Max << endl;
    		outputfile << "The smallest number is:          " << Min << endl;
    		outputfile << "The total of those numbers is:   " << setiosflags(ios::fixed) << Total << endl;
    		outputfile << "The average of those numbers is: " << setprecision(2) << Avg << endl;
    		outputfile << endl;
    	}
    
    	inputfile.close();
    	outputfile.close();
    	return 0;
    }
    Try that..

  4. #4
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    4

    Talking Thanx :-)

    Thanx a lot guys...my teacher wouldn't help me and i don't think that i would've gotten that...i understand now why you have to set the eof at that point...i've been programming c++ like 2 months now...so i'm very new...but anyways...peace

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