链接器错误：“架构 x86_64 的未定义符号”

Question

我正在研究一个骰子类，它允许用户输入骰子的面数并输出每个骰子的滚动数和结果数。我对课程非常陌生，我知道我把它们搞砸了，但现在无法通过它们，因为链接器在 Xcode 和代码块中给了我一个错误。

确切的错误是：

Undefined symbols for architecture x86_64:
  "GameDie::GameDie()", referenced from:
      _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)

这是我的程序代码：

 #include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;

int x = 0;
int sides;

class GameDie
{
public:
    GameDie();
    int roll();
    void getNumSides(int numSides);
    void getNumRolls();
private:
    int numRolls;
    int numSides;
};


int main()
{
    srand(time(0));
    cout << "Enter number of sides: ";
    cin >> sides;

    GameDie die1;
    die1.roll();
    die1.getNumSides(sides);
    die1.getNumRolls();

    return 0;
}


int GameDie::roll()
{
    return (rand() % sides) + 1;
}

void GameDie::getNumSides(int sides)
{
    numSides = sides;
}

void GameDie::getNumRolls()
{
    x++;
    cout << "Roll " << x << " of die with " << sides << " sides";
}

Answer 1

不太确定这个模具类应该如何运行，但我采用了您的代码并尽可能少地进行更改以使其正常运行。这主要是对方法/成员函数的误解。我希望这会有所帮助。

#include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;

int x = 0;
int sides;

class GameDie
{
public:
    GameDie();
    int roll();
    void getNumSides(int numSides);
    void getNumRolls();
private:
    int numRolls;
    int numSides;
};


int main()
{
    srand(time(0));
    cout << "Enter number of sides: ";
    cin >> sides;

    GameDie die1;
    die1.roll();
    die1.getNumSides(sides);
    die1.getNumRolls();

    return 0;
}

GameDie::GameDie()
{
    numSides = 0;
}

int GameDie::roll()
{
    return (rand() % sides) + 1;
}

void GameDie::getNumSides(int sides)
{
    numSides = sides;
}

void GameDie::getNumRolls()
{
    x++;
    cout << "Roll " << x << " of die with " << sides << " sides";
}