Undefined reference to function

[sydfrederick]

So I have a really strange problem occurring...

First, here are the files I'm using:

//pa4.cpp wirtten by Syd Frederick
#include<iostream>
#include<string>
#include<fstream>
#include<sstream>
#include<cctype>
#include<cstdio>
#include "pa4functions.h"

int main(int argc, char* argv[])
{
	using std::cout;
	using std::cin;
	using std::endl;
	using std::string;
	using std::ifstream;

	synopsis();

	string in;

	if (argc <=1)
	{
		cout << "Missing Input File. Use " << argv[0] << " <Filename>" << endl;
		return(1);
	}

	else
	{
		ifstream iFile ( argv[1] );
		
		if ( !iFile.is_open() )
			cout << "Could not open file." << endl;
		else
		{
			cout << endl << "File: " << argv[1] << endl;
			char x;

			while ( iFile.get ( x ) )
			{
				cout << x;
				if (isalpha(x))
				{
					in+=x;
				}					
			}
		}
	iFile.close();
	}

	execute(in);
	return(0);
}	

//Written by Syd Frederick
//Filename: pa4functions.cpp
//

#include<iostream>
#include<cctype>
#include<cstdio>
#include "letter_frequency.h"
#include "ltr_freq_pair.h"

using std::cout;
using std::cin;
using std::endl;
using std::string;

void synopsis()
{
	cout << "This program will take the file you have provided " << endl;
	cout << "and display a letter frequency of the contents. " << endl;
}

void execute(string in)
{
	string temp=in;

	for (int i=0; i<in.size(); i++)
	{
		in[i] = tolower(temp[i]);
	}

	letter_frequency letter_freq;
	
	ltr_freq_pair a_f;
	a_f.x='a';
	a_f.y=0;
	ltr_freq_pair b_f;
	b_f.x='b';
	b_f.y=0;
	ltr_freq_pair c_f;
	c_f.x='c';
	b_f.y=0;
	ltr_freq_pair d_f;
	d_f.x='d';
	d_f.y=0;
	ltr_freq_pair e_f;
	e_f.x='e';
	e_f.y=0;
	ltr_freq_pair f_f;
	f_f.x='f';
	f_f.y=0;
	ltr_freq_pair g_f;
	g_f.x='g';
	g_f.y=0;
	ltr_freq_pair h_f;
	h_f.x='h';
	h_f.y=0;
	ltr_freq_pair i_f;
	i_f.x='i';
	i_f.y=0;
	ltr_freq_pair j_f;
	j_f.x='j';
	j_f.y=0;
	ltr_freq_pair k_f;
	k_f.x='k';
	k_f.y=0;
	ltr_freq_pair l_f;
	l_f.x='l';
	l_f.y=0;
	ltr_freq_pair m_f;
	m_f.x='m';
	m_f.y=0;

	ltr_freq_pair n_f;
	n_f.x='n';
	n_f.y=0;
	ltr_freq_pair o_f;
	o_f.x='o';
	o_f.y=0;
	ltr_freq_pair p_f;
	p_f.x='p';
	p_f.y=0;
	ltr_freq_pair q_f;
	q_f.x='q';
	q_f.y=0;
	ltr_freq_pair r_f;
	r_f.x='r';
	r_f.y=0;
	ltr_freq_pair s_f;
	s_f.x='s';
	s_f.y=0;
	ltr_freq_pair t_f;
	t_f.x='t';
	t_f.y=0;
	ltr_freq_pair u_f;
	u_f.x='u';
	u_f.y=0;
	ltr_freq_pair v_f;
	v_f.x='v';
	v_f.y=0;
	ltr_freq_pair w_f;
	w_f.x='w';
	w_f.y=0;
	ltr_freq_pair x_f;
	x_f.x='x';
	x_f.y=0;
	ltr_freq_pair y_f;
	y_f.x='y';
	y_f.y=0;
	ltr_freq_pair z_f;
	z_f.x='z';
	z_f.y=0;

	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'a')
		{
			a_f.y++;
		}
	}
	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'b')
		{
			b_f.y++;
		}
	}
	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'c')
		{
			c_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'd')
		{
			d_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'e')
		{
			e_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'f')
		{
			f_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'g')
		{
			g_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'h')
		{
			h_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'i')
		{
			i_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'j')
		{
			j_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'k')
		{
			k_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'l')
		{
			l_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'm')
		{
			m_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'n')
		{
			n_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'o')
		{
			o_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'p')
		{
			p_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'q')
		{
			q_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'r')
		{
			r_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 's')
		{
			s_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 't')
		{
			t_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'u')
		{
			u_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'v')
		{
			v_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'w')
		{
			w_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'x')
		{
			x_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'y')
		{
			y_f.y++;
		}
	}

	
	for(int i=0; i<in.size(); i++)
	{
		if(in[i] == 'z')
		{
			z_f.y++;
		}
	}

	letter_freq.push_back(a_f);
	letter_freq.push_back(b_f);
	letter_freq.push_back(c_f);
	letter_freq.push_back(d_f);
	letter_freq.push_back(e_f);
	letter_freq.push_back(f_f);
	letter_freq.push_back(g_f);
	letter_freq.push_back(h_f);
	letter_freq.push_back(i_f);
	letter_freq.push_back(j_f);
	letter_freq.push_back(k_f);
	letter_freq.push_back(l_f);
	letter_freq.push_back(m_f);
	letter_freq.push_back(n_f);
	letter_freq.push_back(o_f);
	letter_freq.push_back(p_f);
	letter_freq.push_back(q_f);
	letter_freq.push_back(r_f);
	letter_freq.push_back(s_f);
	letter_freq.push_back(t_f);
	letter_freq.push_back(u_f);
	letter_freq.push_back(v_f);
	letter_freq.push_back(w_f);
	letter_freq.push_back(x_f);
	letter_freq.push_back(y_f);
	letter_freq.push_back(z_f);

	cout << letter_freq << endl;
}
	

//Written by Syd Frederick
//Filename: pa4functions.h
//
//void synopsis() displays a brief introduction and message to the user about the program
//
//void execute() takes a string created from the file and displays the frequencies
//
#include<string>

#ifndef PA4FUNCTIONS_H
#define PA4FUNCTIONS_H


void synopsis();
void execute(std::string in);

#endif 

When compiling I'm getting a strange error that says :

/tmp/ccdt0Bf9.o: In function `main':
pa4.cpp:(.text+0x1c): undefined reference to `synopsis()'
pa4.cpp:(.text+0x1e7): undefined reference to `execute(std::basic_string<char, std::char_traits<char>, std::allocator<char> >)'
collect2: ld returned 1 exit status 

Seriously, I'm at a a loss. Any help would be greatly appreciated...

[modoran]

Add pa4functions.cpp file as compilation unit.

[heepoo]

compile them using:
gcc -c pa4functions.cpp -o pa4functions.o
compile all of your .cpp files like this and link them with this command:
gcc your files.o -o pa4.exe -static-libgcc -static-libstdc++