Unresolved external symbol error

[treefrog]

I am getting these errors with my code and I don't know how to fix them, any help? The errors are on lines 54 and 55.

1 2 3 4 5 6 7 8

1

1> Chapter 9 Num 3 Int Code.cpp 1>c:\users\david\documents\visual studio 2010\projects\chapter 9 num 3 int code\chapter 9 num 3 int code.cpp(37): warning C4101: 'temp' : unreferenced local variable 1>c:\users\david\documents\visual studio 2010\projects\chapter 9 num 3 int code\chapter 9 num 3 int code.cpp(38): warning C4101: 'a_measured_data' : unreferenced local variable 1>c:\users\david\documents\visual studio 2010\projects\chapter 9 num 3 int code\chapter 9 num 3 int code.cpp(74): warning C4700: uninitialized local variable 'data' used 1>Chapter 9 Num 3 Int Code.obj : error LNK2019: unresolved external symbol "void __cdecl displayMatch(class std::basic_ifstream<char,struct std::char_traits<char> > &,struct SearchParams const &)" (?displayMatch@@YAXAAV?$basic_ifstream@DU?$char_traits@D@std@@@std@@ABUSearchParams@@@Z) referenced in function _main 1>Chapter 9 Num 3 Int Code.obj : error LNK2019: unresolved external symbol "void __cdecl getParams(struct SearchParams &)" (?getParams@@YAXAAUSearchParams@@@Z) referenced in function _main 1>c:\users\david\documents\visual studio 2010\Projects\Chapter 9 Num 3 Int Code\Debug\Chapter 9 Num 3 Int Code.exe : fatal error LNK1120: 2 unresolved externals ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Here is my code.

#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <algorithm>
#include <stdio.h>
using namespace std;

const int MAX_ID = 3345;			// Maximum siteIDNumber
const int MAX_WINDSPEED = 22;		// Maximum windSpeed
const int MAX_DAY = 16;				// Maximum dayOfMonth
const int MAX_TEMP = 30;			// Maximum temperature
const int MAX = 10;					// Max array size

struct measured_data_t
{
	int siteIDNumber, dayOfMonth, 
		windSpeed, temperature;
};

struct SearchParams
{
	int lowsiteIDNumber, highsiteIDNumber,
		lowdayOfMonth, highdayOfMonth,
		lowwindSpeed, highwindSpeed,
		lowtemperature, hightemperature;
};

void getParams( SearchParams& params );
void displayMatch( ifstream& database, const SearchParams& params );

int main()
{
	string datafile;			// Name of file that contains meteorological data
	SearchParams params;
	measured_data_t data[MAX];
	char temp[10];
	measured_data_t a_measured_data;
	int i;
	int n;
	int var;
	int max[3]={0,0,0},min[3],diff[3],avg[3]={0,0,0},count[3]={0,0,0};
	n = 0;

	cout << " Weather and Climate Research Data " << endl; 
	cout << " Temp variation & average wind speed " << endl; 
	
	cout << " Enter name of file that contains meteorological data " << endl;
	cin >> datafile;
	ifstream inventory( datafile.c_str(), ios::in );
	
	if (!inventory.fail())
	{
		getParams( params );
		displayMatch( inventory, params );
		inventory.close();
	}

	else
	{
		cout << " Cannot open file " << datafile << endl;
	}

cout << " site ID, Day of Month, Wind speed, Temp " << endl;
	
	for( i=0; i; )
	{
		cout << " %4d %3d %3d %3d " << endl;
	}

// Gets the different site ID values

	n=0;
	diff[0]=data[0].siteIDNumber;
	for ( i=0; i; )
	{
		if (diff[n]==data[n].siteIDNumber)
	{
	
		continue;
	}
	else
	{
		n++;
		diff[n]=data[n].siteIDNumber;
	}
	}

// Gets the max value of temperature for all individual sites

	n=0;
	for( i=0; i; )
	{
		if (diff[n]==data[n].siteIDNumber)
		{
			if(max[n])
			{
				max[n]=data[n].temperature;
				min[n]=data[n].temperature;
			}
			n++;
		}
	}

// Gets the min value of temperature for all individual sites

	for( i=0; i; )
	{
		for(n=0;n<3;n++)
		{
			if(diff[n]==data[n].siteIDNumber)
			{
				if(min[n]>data[n].temperature)
				min[n]=data[n].temperature;
			}
		}
	}

// Gets the mean wind speed for the given site ID

	for( i=0; i; )
	{
		for(n=0;n<3;n++)
		{
			if(diff[n]==data[n].siteIDNumber)
			{
				avg[n]=avg[n]+data[n].windSpeed;
				count[n]+=1;
				continue;
			}
		}
	}

	cout << " site ID, Max Temp, Min Temp, Variation, Mean Wind speed " << endl;
	for(i=0;i<3;i++)
	cout << diff << max << min << max-min << avg << endl;

// Calculates the value of greatest variation in temperature

	var=0;
	for(n=0;n<3;n++)
	{
		if((max[n]-min[n])>var)
		var=max[n]-min[n];
	}

	cout << " Temperature " << endl;	// Prints the greatest variation in temp among sites
	for(n=0;n<3;n++)
	{
		if((max[n]-min[n])==var)
		cout << " Greatest Variation is at Site Id " << diff[n] << endl;
	}

// Calculates the value of greatest variation for mean wind speed

	var=0;
	for(n=0;n<3;n++)
	{
		if((avg[n]/count[n])>var)
		var=avg[n]/count[n];
	}

	cout << " Mean Wind Speed " << endl;	// This prints out the greatest variation in mean wind speed

	for(n=0;n<3;n++)
	{
		if((avg[n]/count[n])==var)
		cout << " Greatest Variation is at Site ID " << diff[n] << endl;
	}

	system("pause");
	return 0;
}

[vlad from moscow]

Your forgot to define functions

void getParams( SearchParams& params );
void displayMatch( ifstream& database, const SearchParams& params );

[treefrog]

How do I do that again? I just tried and the struct that i created didn't allow me to define it.

[vlad from moscow]

I do not understand what you are speaking about. One more you did not define functions

void getParams( SearchParams& params );
void displayMatch( ifstream& database, const SearchParams& params );

[treefrog]

How do I define those functions?

[vlad from moscow]

Are you asking me?!
I do not know. They are your functions. if you declared them then you should know why you declared them and what they have to do.