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Linker error

tomtom61695 (29)
I have written a program that is separated as three different files. One file is the main, one with the class definition and one with all of the functions. The purpose is to separate a file of DVD's, but I am stuck. When I go to compile the function file, I get this error:

Undefined symbols for architecture x86_64:
"_main", referenced from:
implicit entry/start for main executable
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Help would be greatly appreciated.

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#include <iostream>
#include <cstdlib>
#include <iomanip>
#include <string>
#include <sstream>
#include <fstream>
#include "DVD.hpp"

using namespace std;

DVD::DVD(){
    title = " ";
    year = 1800;
    actor = " ";
}
DVD::DVD(string new_title, int new_year, string new_actor){
    title = new_title;
    year = new_year;
    actor = new_actor;

}
DVD::DVD(string all_data){
    char a, b, c, d;
    //characters, one for each spot in the year;
    int p1, p2, p3;
    p1 = all_data.find("|");//finding where the | is;
    title = all_data.substr(0, p1); //finds title inside the string and sets it to title;
    all_data = all_data.substr(p1+1);
    
    p2 = all_data.find("|"); //finding where the second | is.
    p3 = all_data.length();
    actor = all_data.substr(p2+1, p3);//finds actor inside thr string and sets it to actor;
    all_data = all_data.substr(0, p2);
    
    a = all_data[0]- '0';
    b = all_data[1]- '0';
    c = all_data[2]- '0';
    d = all_data[3]- '0';
    //these four chars get assigned to the year. a becoming the first digit, b becoming the second, c becoming the third and d becoming the fourth;
    
    year = (a * 1000) + (b * 100) + (c * 10) + d;
    
    //since the chars are read in one at a time, we have to multiply them like so to recreate the year for our output.
    
}
void DVD::set_title(string new_title){
    title = new_title;
}

void DVD::set_year(int new_year){
    year = new_year;
}
void DVD::set_actor(string new_actor){
    actor = new_actor;
}

string DVD::get_title(){
    return title;
}
int DVD::get_year(){
    return year;
}
string DVD::get_actor(){
    return actor;
}
bool DVD::match_title(string target_title){
    
    string sub_title = title;
    string sub_target_title = target_title;
    char title_array[1000];
    
    for(unsigned int i = 0; i < sub_title.length(); i++){
        title_array[i] = sub_title[i];
    }
    for(unsigned int k = 0; k < sub_title.length(); k++){
        {
            
        }
        sub_title[k] = title[k];
    }
    
    char target_title_array[1000];
    
    for(unsigned int i = 0; i < sub_target_title.length(); i++){
        target_title_array[i] = sub_target_title[i];
    }
    for(unsigned int k = 0; k < sub_target_title.length(); k++){
        {
            
        }
        target_title[k] = sub_target_title[k];
    }
    if (sub_title.find(sub_target_title) != 999999)
        return true;
    else
        return false;
    
}
bool DVD::match_year(int the_year){
    ostringstream stream1;
    stream1 << year;
    string year = stream1.str();
    
    ostringstream stream2;
    stream2 << the_year;
    string target_year = stream2.str();
    
    if (year.find(target_year) != 999999)
        return true;
    else
        return false;
    
    
    
}
bool DVD::match_actor(string target_actor){
    string sub_actor = actor;
    string sub_target_actor = target_actor;
    char actor_array[1000];
    
    for(unsigned int i = 0; i < sub_actor.length(); i++){
        actor_array[i] = sub_actor[i];
    }
    for(unsigned int k = 0; k < sub_actor.length(); k++){
        {
            
        }
        sub_actor[k] = actor[k];
    }
    
    
char target_actor_array[1000];
    
    for(unsigned int i = 0; i < sub_target_actor.length(); i++){
        target_actor_array[i] = sub_target_actor[i];
    }
    for(unsigned int k = 0; k < sub_target_actor.length(); k++){
        {
            
        }
        target_actor[k] = sub_target_actor[k];
    }
    if (sub_actor.find(sub_target_actor) != 999999)
        return true;
        else
            return false;
        
}
bool DVD::match(string target){
    string year_string = to_string(year);
    if (match_title(target) == 1 || match_actor(target) == 1 || year_string.find(target) != 999999)
        return true;
    else
        return false;
    
}
void DVD::output(){
    cout << title << "|" << year << "|" << actor << endl;
}
TheIdeasMan (6817)
Hi,

Can you please post:

* The compiler error verbatim, we want to see all the error, not part or your interpretation of it :+)
* The DVD.hpp file
* The main.cpp file

Some other things:

Consider using a member initialiser list in your constructors.

Why do you copy individual chars from a std::string to a char array?

Actually, I don't see the point of any of your match functions. It looks like a lot of unnecessary copying culminating in a find statement that is always false. What were you trying to do there?
ne555 (10692)
http://www.cplusplus.com/forum/general/113904/

http://www.cplusplus.com/doc/tutorial/program_structure/
The function named main is a special function in all C++ programs; it is the function called when the program is run. The execution of all C++ programs begins with the main function, regardless of where the function is actually located within the code.
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