XCode C++ linker command failed with exit code 1 (use -v to see invocation)

Question

I am receiving the build fail error of "linker command failed with exit code 1" I have checked other forum posts that talk about duplicate function calls that confuse the linker. I don't have very much experience with C++ so i would love some help!

ld: 1 duplicate symbol for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)

LINE.H

#include <stdio.h>
#include <string>

using namespace std;

class RuntimeException { // generic run-time exception
private:
    string errorMsg;
public:
    RuntimeException(const string& err) { errorMsg = err; }
    string getMessage() const { return errorMsg; }
};

// All that is needed for the special exceptions is the inherited constructor and method.

class EqualLines: public RuntimeException
{
public:
    EqualLines(const string& err)
    : RuntimeException(err) {}
};

class ParallelLines: public RuntimeException
{
public:
    ParallelLines(const string& err)
    : RuntimeException(err) {}
};


class Line {
public:
    Line(double slope, double y_intercept): a(slope), b(y_intercept) {};
    double intersect(const Line L) const throw(ParallelLines,
    EqualLines);
    double getSlope() const {return a;};
    double getIntercept() const {return b;};


private:
    double a;
    double b;
};

LINE.CPP

#include "line.h"
#include <iostream>

double Line::intersect(const Line L) const throw(ParallelLines,
                                                 EqualLines)
{
    if (this->a == L.a && this->b == L.b)
    {
        throw "EqualLines";
    }
    else if (this->a == L.a)
    {
        throw "ParallelLines";
    }

    return (L.b - this->b) / (this->a - L.a);
}

MAIN.CPP

#include "line.cpp"
#include <iostream>

int main()
{
    Line L(2.0, 4.0);
    Line K(3.0, 5.0);

    try
    {
        if (L.getSlope() == K.getSlope() && L.getIntercept() == K.getIntercept())
            throw EqualLines("The lines are equal: infinite intersection");
        else if (L.getSlope() == K.getSlope())
            throw ParallelLines("The lines are parallel: no intersection");
    }
    catch(EqualLines& zde)
    {

    }
    catch(ParallelLines& zde)
    {

    }

    cout << "Line 1: Y = " << L.getSlope() << "x + " << L.getIntercept();

    cout << "\n";

    cout << "Line 2: Y = " << K.getSlope() << "x + " << K.getIntercept();

    cout << "\n\n";


    L.intersect(K);


    return 0;
}

Answer 1

在您的主文件中，您应该包含.h文件而不是.cpp 。