Beginner Problem

This is a discussion on Beginner Problem within the C++ Programming forums, part of the General Programming Boards category; Alright, I'm a mechanical engineering student taking a mandatory C++ course and I am absolutely terrible at it. I currently ...

  1. #1
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    Beginner Problem

    Alright, I'm a mechanical engineering student taking a mandatory C++ course and I am absolutely terrible at it. I currently need to write a program that I've been trying to write for a week and it's already late. I need to write a function for computing a moving average that is callable from main. If anyone can help me I'd really appreciate it.

  2. #2
    Registered User major_small's Avatar
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    did you read the tutorial on functions?
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    I have a basic understanding, and I'm able to write the moving average function, I just don't understand at all how to make one that is callable from another function.

  4. #4
    Registered User major_small's Avatar
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    well, what do you have so far?
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  5. #5
    Devil's Advocate SlyMaelstrom's Avatar
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    Can you show us the math you're using to compute the moving average then I'll try to show you how to make it into a program.
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  6. #6
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    This is what I have so far

    Code:
    #include <iostream>
    #include <fstream>
    
    using namespace std;
    
    const int N=1000;
    
    
    int process_speed_data(const double x[N], int n);
    int main()
    {
    	ifstream in;
    	int count(0), data;
    	double data[N], average[N];
    	double sum_1(0), sum_2(0);
    
    	in.open("sensor.dat");
    
    	while (count < (N-1) && !in.eof())
    	{
    		in >> data[count];
    		count++;
    	}
    	cout << main(data, count)
    	
    	
    	
    	//Set first 9 elements of averages array to 0.
    	for( int i = 0; i < 9 ; i++ ) 
    	{
            sum_1 += data[i];
    		average[i] = sum_1 / (i+1) ;
    	}
    	 //Record moving averages for the remaining elements.
    	for( int i = 9; i<=count ; i++ ) 
    	{
    		sum_2 = 0;
    
    		for( int j = i - 9; j <= i; j++) 
    		{			
    			sum_2 += data[j];
    		}
    		average[i] = sum_2 / 10;
    	}
    	
    	
    	for( int i = 0; i < count; i++ )
    	{
    		cout << average[i]
    	}
    
    		
    
    }
    EDIT: This code is choppy, the exact assignment is to make the reading and averaging of the data a callable function (process_speed_data) from a primary main function.
    Last edited by knoxmaddog; 11-21-2005 at 09:26 PM.

  7. #7
    Devil's Advocate SlyMaelstrom's Avatar
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    Code:
    cout << main(data, count)
    What are you trying to do here? Is this where you want to call the function?
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    I need to make a main function and have the filtering of the data occur in a second function which is called from main.

  9. #9
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    This one actually works, sorry about that other one

    Code:
    #include <iostream>
    #include <fstream>
    
    using namespace std;
    
    const int N=1000;
    
    
    int main()
    {
    	ifstream in;
    	int count(0), data;
    	double prices[N], averages[N];
    	double sum_1(0), sum_2(0);
    	
    	
    	in.open("sensor.dat");
    
    	while (count < (N-1) && !in.eof())
    	{
    		in >> prices[count];
    		count++;
    
    	}
    	
    	
    
    	//Set first 19 elements of averages array to 0.
    	for( int i = 0; i < 9 ; i++ ) 
    	{
            sum_1 += prices[i];
    		averages[i] = sum_1 / (i+1) ;
    	}
    	
    
    	 //Record moving avergaes for the remaining elements.
    	for( int i = 9; i<=count ; i++ ) 
    	{
    		sum_2 = 0;
    		for( int j = i - 9; j <= i; j++  ) 
    		{			
    			sum_2 += prices[j];
    		}
    		averages[i] = sum_2 / 10;
    	}
    	
    	
    	for( int i = 0; i < count; i++ ) {
    
    		cout << i << " average = " << averages[i] << endl;
    	}
    }

  10. #10
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    Code:
    // Stuff...
    int Function( Parameters for calculating speed stuff )  // int Function( int stuff ) for example
    {
      // Calculate speed stuff
      return speed stuff;
    }
    
    int main()
    {
      //Read in the data
      cout << Function( Pass data needed to calculate speed stuff );  // Function( 32 ) for example
      return 0;
    }
    That should give you the idea of using a function...

    - SirCrono6
    Last edited by SirCrono6; 11-21-2005 at 09:40 PM.
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  11. #11
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    So basically, i should read the data out of the file in main into an array, then send that data to the function to be averaged.

  12. #12
    Rabite SirCrono6's Avatar
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    Yes, I just skimmed your code to get the idea of what you were doing.
    From C to shining C++!

    Great graphics, sounds, algorithms, AI, pathfinding, visual effects, cutscenes, etc., etc. do NOT make a good game.
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  13. #13
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    Thanks for the help, I'm going to try that, knowing my luck with this, I'll be back.

  14. #14
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    Haly crap, thanks for the help, I finally figured it out. You've managed to do in 5 seconds what my professor couldnt explain in the past 3 weeks. Thanks.

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