c++ sort flights by departure and destination

Question

I have a project for school. Need to read file and sort it by destinatiion, departure (24 hour format) , flightNo and gateNo. I tried to sort but it didn't work.. I am new in programming,and if anyone can help me, I'll appreciate.

// Name        : Flight.h

#pragma once
#include <iostream>
#include <string>
#include <vector>
using std::string;

class Flight
{
private:
    string flightNo;
    string destination;
    string departure;
    string gateNo;

public:
    Flight(void);
    ~Flight(void);
    void readingFile();
    void writingFile();

};

// Flight.cpp

#include "Flight.h"
#include <fstream>
#include <cstring>

using namespace std;

Flight::Flight(void)
{
}

Flight :: ~Flight(void)                 
{
}

void Flight :: readingFile()
{
    string FileName;
    string line;
    cout << "Enter a file name: " << endl;  
    cin >> FileName;
    ifstream inFile(FileName.c_str());
    if (inFile.is_open())
    {
        while (getline( inFile, line))
        {
            cout << line <<endl;
        }
        inFile.close();
    }else
        cout << "File is not open!" <<endl;
}
//Sort.h  
#pragma once

#include "Flight.h"
#include <vector>


// Sort class
class Sort
{
protected:
    // number of comparisons performed in sort function
    unsigned long num_cmps;
public:
    // main entry point
    //virtual void sort(vector<Flight>& data) = 0;     
    void sortflights();
    // returns number of comparisons
    unsigned long getNumCmps();
    // resets the number of comparisons
    void resetNumCmps();
};

// SelectionSort class
class SelectionSort : public Sort
{
public:
    // main entry point
    void sort(std::vector<Flight>& data);
};

class MergeSort : public Sort
{
    // main entry point
    void sort(std::vector<Flight>& data);
};


//Sort.cpp
#include "Sort.h"
#include <iostream>

using namespace std;

unsigned long Sort::getNumCmps()
{
    return num_cmps;
}


void Sort::resetNumCmps()
{
    num_cmps = 0;
}

void Sort :: sortflights()
{
    int choose;
    cout<<"Choose an option!"<<endl;
    cout<<"PRESS 1 FOR SORT BY DESTINATION"<<endl;
    cout<<"PRESS 2 FOR SORT BY DEPARTURE"<<endl;
    cout<<"PRESS 3 FOR SORT BY FLIGHT NUMBER"<<endl;
    cout<<"PRESS 3 FOR SORT BY GATE NUMBER"<<endl;
    cin>>choose;

    if(choose==1)
    {

        vector<string> destination;

        for(int i=0; i<destination.size(); i++)
        {
            string elem1=destination[i];
            string elem2=destination[i+1];

            if (strcmp(elem1.c_str(),elem2.c_str())>0)
            {
                cout << elem1<<endl ;
            }
            else
                cout << elem2<<endl ;
            cout << "Number of iteration = " << i << endl;
        }

    }
    else if(choose==2)
    {


        vector<string> departure;

        for(int i=0; i<departure.size(); i++)
        {}

Answer 1

First off, there is no reason for flight number and gate number to be strings. they are just numbers. Translate the string from the file to an int. If you can't use stl, you'll just have to keep the datetime as a string I guess :(

Break this into pieces. You need three different comparisons: numeric, datetime, and lexicographical, depending on what you are sorting by.

A numeric sort is just number comparison: if( a < b ).

A lexicographical sort is relatively simple. Characters are just 8 bit numbers that map to a glyph stored somewhere. You can compare the strings character by character the same way you compare ints. Once you find characters that differ from each other, you can compare the chars and determine which is greater.

Datetime will be tricky without stl. You'll have to find a way to parse the string into something you can compare. Google ways to parse that string.

The only thing left is your sorting algorithm. Visit the Wikipedia pages on Insertion sort, Merge sort, Quicksort, and Selection sort. They give detailed descriptions on how each algorithm works, and in most cases pseudocode on their implementation.

There's really not much else to say on this subject.