lab 8 code

//Module 2
//hydro.cpp

#include<iostream>
#include <fstream>
using namespace std;
#include "list.cpp"
#include "hydro.h"



int main()
{
	Flowlist list();
	int records;
	displayHeader(list, records);



	int choice;
	while(1){
		choice = menu();

		//Display records
		if(choice == 1){
			display(list, records);
			pressEnter();
		}

		//Add Data to linked list
		if(choice == 2){
			addData(list, records);
			pressEnter();
		}

		//save data to text file
		if(choice == 3){
			saveData(list, records);
			pressEnter();
		}

		//remove data from linked list
		if(choice == 4){
			void removeData(list, records);
			pressEnter();
		}

		if(choice == 5){
			cout<<"program terminated";
			break;
		}
	}

	return 0;
}

void displayHeader(Flowlist &list, int &records){
	cout<<"Program: Flow Studies - Fall 2017"<<endl;
	cout<<"Version: 1.0"<<endl;
	cout<<"Lab section: B03"<<endl;
	cout<<"Produced by:     "<<endl;
	pressEnter();
	records = readData(list);
}

void pressEnter(){
	cout<<"<<< Press Enter to Continue >>>"<<endl;
	while(1){
		if (cin.get() == '\n')
			break;
	}
}

int readData(Flowlist &list)
{
	int rec = 0;
	ifstream flow("flow.txt", ios::in);
	if(flow.fail()){
		cerr<<"file not found"<<endl;
		exit(1);
	}

	Node *item = new Node;
	while(!flow.eof()){
		flow>>item.year>>item.flow;
		list->Flowlist::insert(item);
		rec++;
	}
	flow.close;
	return rec;
}

int menu()
{
	cout<<"Please select on the following operations"<<endl;
	cout<<"	1. Display flow list, average and median"<<endl;
	cout<<"	2. Add data."<<endl;
	cout<<"	3. Save data into the file"<<endl;
	cout<<"	4. Remove data"<<endl;
	cout<<"	5. Quit"<<endl;
	cout<<"	Enter your choice (1, 2, 3, 4, of 5): "<<endl;
	int choice = 0;
	while((choice < 1) || (choice > 5))
		cin>>choice;

	return choice;
}

//Option 1
void display(const Flowlist &list, const int &records)
{

	cout<<"Year     Flow (in billions of cubic meters)"<<endl;
	cout<<"----     ----------------------------------"<<endl;


	for(int i = 0; i < records; i++)
		cout<<list.Flowlist::get_year(i)<<"     "<<list.Flowlist::get_flow(i);

	double ave = average(list, records);
	double med = median(list, records);
	cout<<"The annual average of the flow is: "<<ave<<" millions cubic meter"<<endl;
	cout<<"The median flow is: "<<med<<" millions cubic meter."<<endl;
}

double average(Flowlist &list, int &records)
{
	double sum = 0;

	for(int i = 0; i < records; i++)
	{
		sum += list.Flowlist::get_flow(records);
	}

	return sum/records;
}

double median(Flowlist &list, int &records)
{
	double median = 0;
	Node *middle;
	if(records%2 = 0)
	{
		middle = Flowlist::read_item(list, records/2);
		median += middle.item.flow;

		middle = Flowlist::read_item(list, ((records/2)+1));
		median += middle.item.flow;

		median = median/2;
	}
	else
	{
		middle = Flowlist::read_item(list, ((records/2)+1));
		median += middle.item.flow;
	}

	return median;
}

//Option 2
void addData(Flowlist &list, int &records)
{
	Node* n = new Node;
	cout<<"Please enter a year:";
	cin>>n.item.year;
	cout<<endl<<"Please enter the flow";
	cin>>n.item.flow;
	if(!Flowlist::year_exists(n.year))
	{
		cout<<"Error: duplicate data."<<endl;
		pressEnter();
	}
	else
	{
		Flowlist::insert(list, n);
		records++;
	}
}

//Option 3
void saveData(Flowlist &list, int &records)
{
	ofstream flow("flow.txt", ios::out);
	if(flow.fail()){
		cerr<<"file not found"<<endl;
		return;
	}

	for(int i = 0; i < records; i++)
		flow<<list.Flowlist::get_year(i)<<"     "<<list.Flowlist::get_flow(i);

}

//Option 4
void removeData(Flowlist &list, int &records)
{
	int y;
	cout<<"Please enter the year that you want to remove: ";
	cin>>y;
	cout<<endl;

	if(!list.Flowlist::year_exists(y)){
		cerr<<"Error: year is not in list"<<endl;
		return;
	}

	list.Flowlist::removeyear(y);
	records--;
	return;

}