how to get the min & max of a file

This is a discussion on how to get the min & max of a file within the C++ Programming forums, part of the General Programming Boards category; Quick question, so I need to get the min and max of a file. The numbers in the file are: ...

  1. #1
    Registered User
    Join Date
    Sep 2007
    Posts
    29

    how to get the min & max of a file

    Quick question, so I need to get the min and max of a file. The numbers in the file are:
    3
    5
    8
    4

    and this is my code:

    Code:
    /* Write a program that will search a file of numbers
    of type int and write the largest and the smallest numbers
    to the screen. The file contains nothing but numbers of
    type int separated by blanks or line breaks. If this is being
    done as a class assignment, obtain the file name from your
    instructor. */
    
    #include <iostream>
    #include <fstream>
    #include <cstdlib>
    #include <iomanip>
    #include <stdlib.h>
    using namespace std;
    
    void make_neat(ifstream& messy_file, ofstream& neat_file,
    int number_after_decimalpoint, int field_width);
    
    int main ()
    {
            using namespace std;
            ifstream in_stream;
            ofstream out_stream;
    
            in_stream.open("infile.txt");
            out_stream.open("outfile.txt");
    
            if (in_stream.fail( ))
            {
                    cout << "Input file opening failed.\n";
                    exit(1);
            }
            if (out_stream.fail( ))
            {
                    cout << "Output file opening failed.\n";
                    exit(1);
            }
    
            make_neat(in_stream, out_stream, 5, 1);
    
            int largest, smallest;
            in_stream >> largest >> smallest;
            out_stream << "largest = " 
                       << largest << endl;
            out_stream << "smallest = "
                       << smallest << endl;
    
            in_stream.close( );
            out_stream.close( );
    
            return 0;
    }
    
    void make_neat(ifstream& messy_file, ofstream& neat_file,
                  int number_after_decimalpoint, int field_width)
    {
            neat_file.precision(number_after_decimalpoint);
    
            cout.precision(number_after_decimalpoint);
    
            double next;
            while (messy_file >> next)
            {
                    cout << setw(field_width) << next << endl;
                    neat_file << setw(field_width) << next << endl;
            }
    }
    Right now it is just displaying all of the numbers from the file and I'm really kind of stuck... any help is MUCH appreciated!

  2. #2
    Registered User
    Join Date
    Jan 2005
    Posts
    7,340
    You need a variable to remember the current max, and then as you read in each number check to see if it is higher. Do something similar with the min.

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