CODEWITHSUNDEEP
c++
Rishav Basu
Rishav Basu

Reputation: 21

Using data structure methods in main class c++

I'm trying to access methods in my Element structure in my main method. I keep getting an error stating that

"Undefined symbols for architecture x86_64:

"Element::Element()", referenced from:

_main in Element.o

_main in main.o

ld: symbol(s) not found for architecture x86_64

clang: error: linker command failed with exit code 1 (use -v to see invocation)"

Element header

#ifndef Element_hpp
#define Element_hpp

struct Element {
public:
    int getNumber(void);
    void setNumber(int n);
    int getSteps();
    void setSteps();
    Element();
private:
    int number;
    int stepN;
};

#endif /* Element_hpp */

Element class

#include "Element.hpp"
#include "main.cpp"

int Element::getNumber() {
    return number;
}

void Element::setNumber(int n) {
    number = n;
    setSteps();
}

int Element::getSteps() {
    return stepN;
}

int steps(int n) {
    int i = 0;
    int j = n;
    while(j != 1) {
        if(j % 2 == 1) {
            j = (3 * j + 1) / 2;
            i = i + 2;
        }
        else if(j % 2 == 0) {
            j= j / 2;
            i= i + 1;
        }
    }
    return i;
}

void Element::setSteps() {
    stepN = steps(number);
}

Main class

#include <iostream>
#include <String>
#include <fstream>
#include "Element.hpp"


int main(int argc, const char * argv[]) {
    std::ofstream data;
    data.open("data.txt");
    int end = 1000;
    Element* e = new Element[end];
    for(int i = 0; i < end; i++) {
        e[i].setNumber(i);
        e[i].setSteps();
    }
    heapSort(e, end);
    printArray(e, end);
    data.close();
    return 0;
}

Upvotes: 1

Views: 76

Answers (3)

Rishi
Rishi

Reputation: 1395

You have declared Element(); constructor in Element header file but you have not defined it in any file.

You may want to add this in your Element implementation file:

Element::Element() {
}

Upvotes: 1

bruno nery
bruno nery

Reputation: 2052

As Sam Varshavchik mentioned in the comment, you declared

Element::Element()

on your Element header file but did not define it. Adding

Element::Element() {
}

to your Element class file should allow the linker to find the missing symbol.

Upvotes: 1

Code-Apprentice
Code-Apprentice

Reputation: 83557

You should never #include CPP files. Instead you should link them. The most straight forward way is from the command line:

$ g++ main.cpp element.cpp

I suggest that you read about the C++ build process including the difference between compiling and linking.

Upvotes: 1

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