Finding Max and Min Value

This is a discussion on Finding Max and Min Value within the C++ Programming forums, part of the General Programming Boards category; Hi, The problem is that I have a program which processes a 2D array. One task is to find the ...

  1. #1
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    Nov 2006
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    Finding Max and Min Value

    Hi,
    The problem is that I have a program which processes a 2D array. One task is to find the min and max of one column (ignoring the second). Here is my code so far:
    Code:
    #include <iostream.h>
    #include <stdlib.h>
    #include <fstream>
    
    using namespace std;
    
    double data[4][2]; // declare 2D array for data in file.
    int count;
    int noOfReadings;
    int counter=0;
    int numberOfSpeedIntervals;
    int numberOfSectors;
    
    int main()
    {
     ifstream inPutFile;//Creates stream to input file.
     inPutFile.open("c:\\grade.txt");//Opens stated file.
    
     if (!inPutFile)//Deals with problems opening file.
          cout << "Error opening file!" << endl;
    
    //Finds how many lines of data there are.
    int item;
    while (!inPutFile.eof())
    {
    inPutFile >> item;
    counter++;
    }
    const int rows = (counter/2);
    cout<<"Number of rows: "<<rows<<endl;
    
    cout<<"Please type how many intervals do you require: ";
    cin>> numberOfSpeedIntervals;
    
    cout<<"Please type how many sectors do you require: ";
    cin>> numberOfSectors;
    
    //initialise current max and min
       // find max and min
       // initialise current max and min
      double maxRead = data[i][0];
      double minRead = data[i][0];
      
      for (int i = 1; i < data; i++)
      {
      
         if (maxRead < data[i])
         {
            maxRead = data[i];
         }
         
         if (minRead > data[i])
         {
             minRead = data[i];
         }    
       
      }
    
          system("PAUSE");
          return 0;
    }
    The last lines are faulty. Any ideas?

    Will

  2. #2
    CSharpener vart's Avatar
    Join Date
    Oct 2006
    Location
    Rishon LeZion, Israel
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    for (int i = 1; i < data; i++)
    the limit is incorrect - should be 4 (best declare it as const somewhere and use in every place in the code you need the array size)
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  3. #3
    Registered User
    Join Date
    Nov 2006
    Posts
    10
    Thanks,
    I changed data to rows which is the user set variable set by user. Code now reads:
    Code:
    .
    .
    .
    .
    while (!inPutFile.eof())
    {
    inPutFile >> item;
    counter++;
    }
    const int rows = (counter/2);
    cout<<"Number of rows: "<<rows<<endl;
    .
    .
    .
    .
    //initialise current max and min
       // find max and min
       // initialise current max and min
      double maxRead = data[0][0];
      double minRead = data[0][0];
      
      for (int i = 1; i < rows; i++)
      {
      
         if (maxRead < data[i][0])
         {
            maxRead = data[i][0];
         }
         
         if (minRead > data[i][0])
         {
             minRead = data[i][0];
         }    
    
      cout<<"Min= "<<minRead<<endl;
      cout<<"Max= "<<maxRead<<endl;
    
      }
    
          system("PAUSE");
          return 0;
    }
    I get max and min returned as zero. Any ideas?
    Cheers
    Will

  4. #4
    CSharpener vart's Avatar
    Join Date
    Oct 2006
    Location
    Rishon LeZion, Israel
    Posts
    6,484
    you havn't initialized the data array
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

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