How to get data file name from other function?

[Haziq]

Hello and good day. How do i set myfile from searchstat() to get the file from loaddata() ?

void loaddata()
{
ifstream myfile;
	while(!myfile.is_open()) 
	{
		cout << "   Input data file: ";
		cin >> file;
		myfile.open(file.c_str(),ios::in | ios::binary);
		
		if ((file != "weather.txt") && (file != "weather2.txt"))
	        {
		cout <<"\n   File not found. " << endl;
		endprogram();
		}
	}
}
void SearchStat()
	{
	string line, file, type, thedate;
	string date;
	double lowTemp, highTemp, rainfall;
	
		ifstream myfile;
		getline(myfile, line); 
		{
			cout <<"\n\n     Format (year-month-date)";
			cout <<"\n     Enter the date you desired :  " ;
			cin >> date;
		
			bool found = false;
			while(getline( myfile, line ) && !found)
			{
				if(line.find(date) != string::npos)
				{ 									
				cout <<"\n     "<<line << endl;
					found = true;
					// Break not necessary although its correct
				}
			}

			if (!found){
				Sleep(2000);
				cout << "\n\n   NOT FOUND" << endl; }
				endprogram();
		
		}
		
	}

[TarikNeaj]

You can create the file in SearchStat and pass it by reference -

http://www.learncpp.com/cpp-tutorial/73-passing-arguments-by-reference/

[Haziq]

How do i pass string by reference?

[TarikNeaj]

Same was as with integer.

void pass(string& fileName)

[Haziq]

in my main function.. i use switch and what about this?

case 1 : WeatherReports.LoadData(file);
			         break;

its an error if i put file or &file.

[TarikNeaj]

Well, I don't know what your new code is. The function you showed earlier is called loaddata and not LoadData.

What errors are you getting, copy paste the full messages.

[Haziq]

If i put ...LoadData(file); it gives 'file' not declared. If i put string, "error: expected primary-expression before '&' token. i'm not sure how to copy and paste from command prompt

[Haziq]

www.cpp: In function 'int main()':
www.cpp:235:37: error: no matching function for call to 'Weather::LoadData()'
case 1 : WeatherReports.LoadData();
^
www.cpp:235:37: note: candidate is:
www.cpp:38:9: note: void Weather::LoadData(std::string&)
void LoadData(string &filename)
^
www.cpp:38:9: note: candidate expects 1 argument, 0 provided

D:\>g++ www.cpp
www.cpp: In function 'int main()':
www.cpp:236:37: error: no matching function for call to 'Weather::LoadData()'
case 1 : WeatherReports.LoadData();
^
www.cpp:236:37: note: candidate is:
www.cpp:38:9: note: void Weather::LoadData(std::string&)
void LoadData(string &filename)
^
www.cpp:38:9: note: candidate expects 1 argument, 0 provided

D:\>g++ www.cpp
www.cpp: In function 'int main()':
www.cpp:236:37: error: 'file' was not declared in this scope
case 1 : WeatherReports.LoadData(file);
^

D:\>g++ www.cpp
www.cpp: In function 'int main()':
www.cpp:236:44: error: expected primary-expression before '&' token
case 1 : WeatherReports.LoadData(string &file);
^
www.cpp:236:45: error: 'file' was not declared in this scope
case 1 : WeatherReports.LoadData(string &file);
^

D:\>g++ www.cpp
www.cpp: In function 'int main()':
www.cpp:237:43: error: no matching function for call to 'Weather::LoadData(std::string*)'
case 1 : WeatherReports.LoadData( &file);
^
www.cpp:237:43: note: candidate is:
www.cpp:38:9: note: void Weather::LoadData(std::string&)
void LoadData(string &filename)
^
www.cpp:38:9: note: no known conversion for argument 1 from 'std::string* {aka std::basic_string<char>*}' to 'std::string& {aka std::basic_string<char>&}'

D:\>g++ www.cpp
www.cpp: In function 'int main()':
www.cpp:237:44: error: expected primary-expression before '&' token
case 1 : WeatherReports.LoadData(string &file);
^

D:\>g++ www.cpp
www.cpp: In function 'int main()':
www.cpp:237:37: error: 'file' was not declared in this scope
case 1 : WeatherReports.LoadData(file);
^

D:\>g++ www.cpp
www.cpp: In function 'int main()':
www.cpp:237:37: error: 'file' was not declared in this scope
case 1 : WeatherReports.LoadData(file);
^

D:\>g++ www.cpp
www.cpp: In function 'int main()':
www.cpp:237:44: error: expected primary-expression before '&' token
case 1 : WeatherReports.LoadData(string &file);
^

[TarikNeaj]

Your errors are pretty obvious -

error: no matching function for call to 'Weather::LoadData()'

You're calling a function that doesnt exist.

error: 'file' was not declared in this scope

"file" most likely dosent exist where you're trying to use it, the variable is non-existant.

Hard to comment when you're errors are in a program I cant see.

[Haziq]

Here's my full code

#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <cstdlib>
#include <windows.h>
using namespace std;


void endprogram();
class Weather
{
	// reports of the same year

	struct entry
	{
		int year;
		double avg_min_tmp;
		double avg_max_tmp;
		double rain;

		vector<string> description;
		vector<int> count; // counter


	};

	vector<entry> Reports; // reports from different years

public:

   Weather(){
		// create fresh instance of the vector
	   Reports = vector<entry>();
   }

	
   void LoadData(string &filename)
   {
	   string file;
	   int number_of_lines = 0;
	   
	ifstream myfile;
	while(!myfile.is_open()) 
	{
		cout << "   Input data file: ";
		cin >> file;
		myfile.open(file.c_str(),ios::in | ios::binary);
		
		if ((file != "weather.txt") && (file != "weather2.txt"))
	    {
		cout <<"\n   File not found. " << endl;
		endprogram();
		}
	}
	
		while (!myfile.eof ())
		{
			getline(myfile, file);
			if (file=="") //error checking
			{
				cout << endl;
				number_of_lines=0; //if not true
			}
			else 
			{
				++number_of_lines; //count lines in weather.txt
			}
			
		}	
		cout <<"   Loading. . . . ." << endl;
		Sleep(2000);
		
		
	   while(true)
		{

		   int year, rainfall;
		   string type;
		   double lowtemp, hightemp;

		   myfile >> year >> type >> lowtemp >> hightemp >> rainfall;

		   if(myfile.eof())
			   break;
		   cout<<" Read "<<year<<" "<<type<<" "<<lowtemp<<" "<<hightemp<<" "<<rainfall<<endl;


		   int i, j;
		   for (i=0; i<Reports.size(); i++)
		   {
			   if(Reports[i].year !=year)
				   continue;


			   int n = Reports[i].description.size();

			   Reports[i].rain += rainfall;
			   Reports[i].avg_min_tmp = (Reports[i].avg_min_tmp*(n) + lowtemp)/(n+1);
			   Reports[i].avg_max_tmp = (Reports[i].avg_max_tmp*(n) + hightemp)/(n+1);


			   vector<string> descrip = Reports[i].description;
			   for(j=0; j<descrip.size(); j++)
			   {
				   if(descrip[j].compare(type) != 0)
					   continue;

				   Reports[i].count[j]++;
				   break;

			   }

			   if(j ==descrip.size()){
				   Reports[i].description.push_back(type);
				   Reports[i].count.push_back(1);

			   }
			   break;
		   }

		   if (i == Reports.size()){

			   struct entry NewEntry;
			   NewEntry.year = year;
			   NewEntry.avg_min_tmp = lowtemp;
			   NewEntry.avg_max_tmp = hightemp;
			   NewEntry.rain = rainfall;
			   NewEntry.description.push_back(type);
			   NewEntry.count.push_back(1);

			   Reports.push_back(NewEntry);
		   }

		  // number_of_lines++;

		}
		cout <<"   Successfully loaded "<< number_of_lines<< " entries!" << endl; 
		endprogram();
	}	
	 
	
	
   

   void OverallStats()
   {
	   system("cls");
	   for(int i = 0; i<Reports.size(); i++)
	   {
		   cout<<"Year: "<<Reports[i].year<<endl;
		   cout<<"\tAvg minimum temperature: "<<Reports[i].avg_min_tmp<<" C"<<endl;
		   cout<<"\tAvg maximum temperature: "<<Reports[i].avg_max_tmp<<" C"<<endl;
		   cout<<"\tTotal rainfall: "<<Reports[i].rain<<" mm"<<endl;
		   cout<<"\tDays where reported weather is:"<<endl;

		   for(int j=0; j<Reports[i].description.size(); j++)
		   {
			   cout<<"\t\t"<<Reports[i].description[j];
			   cout<<"\t"<<Reports[i].count[j]<<endl;
		   }
		   cout<<endl;
	   }

	endprogram();
   }

   
    void SearchStat()
	{
	string line, file, type, thedate;
	string date;
	double lowTemp, highTemp, rainfall;
		
		ifstream myfile;
		LoadData(file);
		getline(myfile, line); 
		{
			cout <<"\n\n   Format (year-month-date)";
			cout <<"\n   Enter the date you desired :  " ;
			cin >> date;
		
			bool found = false;
			while(getline( myfile, line ) && !found)
			{
				if(line.find(date) != string::npos) // Search year followed by month and date respectively
				{ 									// ::npos = "until the end of the string".
					
					cout <<"\n   "<<line << endl;
					cout <<"\n ============================================" << endl;
					found = true;
					// Break not necessary although its correct
				}
			}

			if (!found){
				Sleep(2000);
				cout << "\n\n   NOT FOUND" << endl; }
				endprogram();
		
		}
		
	}


};

void Menu()
{
	cout <<" ============================================" << endl;
	cout <<" * Welcome to xyz weather stats generator * " << endl;
	cout <<" ============================================" << endl;
	cout <<"   Menu options :" << endl;
	cout <<"\n     1. Load data file";
	cout <<"\n     2. Overall stats";
	cout <<"\n     3. Search by date";
	cout <<"\n     4. Monthly stats";
	cout <<"\n     5. Quit";
	cout <<"\n ============================================" << endl;
	cout<<endl<<"   User Options: ";
	return;
}

int main(){

	Weather WeatherReports;
	system("cls");
	string file;
	int option;
	bool quit = false;
	while(!quit){

		Menu();
		cin>>option;
		switch(option){

			case 1 : WeatherReports.LoadData(string &file); //HERE! 
			         break;

			case 2 : WeatherReports.OverallStats();
			         break;

			case 3 : WeatherReports.SearchStat();
			         break;

			case 5:
				{
					cout <<"\n ============================================" << endl;
					cout<<"       You've chose to quit the program.";
					cout<<"\n          Thank you and Goodbye.";
					cout <<"\n ============================================" << endl;
					exit(1);
				}
			default:
				{
					system("cls");
					cout <<"\n ============================================" << endl;
					cout <<"\n     Invalid selection. Program ends.\n";
					cout <<"\n ============================================" << endl;
					exit(1);
					break;
				}
			}


	}
	return 0;



}

void endprogram() 
{
	string end;
	cout << endl;
	cout <<"\n   Please press any key to continue,";
	cout <<"\n   Press N or n to exit the program => ";
	cin >> end;
	
	
	if((end[0] == 'N')||(end[0] == 'n'))
	{
		cout <<"\n ============================================" << endl;
		cout<<"       You've chose to quit the program.";
		cout<<"\n          Thank you and Goodbye.";
		cout <<"\n ============================================" << endl;
		exit(1);
	}
	else
	{
		system("cls");
		return;
	}
	
}


/*cout<<"   Enter year: ";
		int year;
		cin>>year;
		int i;
		for(i=0; i<Reports.size(); i++)
		{

			if(Reports[i].year!=year)
				continue;

			cout<<"Year: "<<Reports[i].year<<endl;
			cout<<"\tAvg. minimum temperature: "<<Reports[i].avg_min_tmp<<" C"<<endl;
			cout<<"\tAvg. maximum temperature: "<<Reports[i].avg_max_tmp<<" C"<<endl;
			cout<<"\\tDays where reported weather is:"<<endl;

			for(int j=0; j<Reports[i].description.size(); j++)
			{
				cout<<"\t\t"<<Reports[i].description[j];
				cout<<"\t"<<Reports[i].count[j]<<endl;
			}
			cout<<endl;
			break;
		}

		if(i==Reports.size())
			cout<<"\n   No entry for year "<<year<<" was found"<<endl;
			endprogram();*/

[TarikNeaj]

case 1 : WeatherReports.LoadData(string &file); //HERE! 
			         break;

			case 2 : WeatherReports.OverallStats();
			         break;

			case 3 : WeatherReports.SearchStat();
			         break;

You're using a Weather Object to call these 3 functions. But that only works if the functions are part of the class, which they are not. So you can't call them this way, you should revisit classes and make it proparly -

http://www.cplusplus.com/doc/tutorial/classes/