无法解决错误：链接器命令失败，退出代码为1

Question

尝试创建一个类帐户，但每次构建时我都会继续“链接命令失败，退出代码为1”。任何建议都会受到高度赞赏，因为我一直试图解决这个问题几天。

#include <iostream>
using namespace std;

class Account
{
public:
Account();
Account(double input_balance);

void input();
private:
double balance;
};


Account::Account()
{   
double balance = 0.0;
}
Account::Account(double input_balance)
{
double balance = input_balance;
}

void Account::input()
{
char in;
    cout << "Would you like to deposit or withdraw money from your account?    Enter D for deposit and W for withdraw: ";
cin >> in;

if(in == 'd' || in == 'D')
    cout << "Yo";
if(in == 'w' || in == 'W')
    cout << "no";
}

int main()
{
Account tyler;
tyler.input();
}