c++ - C++错误 “_main”，引用自:“Xcode

Question

我不断收到此错误“_main”，引用自:...”我是C++的新手，Xcode可以向我解释为什么我收到此错误，以及需要怎么做才能解决它？
谢谢

#ifndef bank_h
#define bank_h
#include <iostream>
//using namespace std;
namespace bank_hw
{
    class bank
    {
        public:
            int accountNumber;
            std::string owner;
            std::string newOwner;
            double balance;
    
        public:
            //default constructor
            bank();
            bank(int accountNumber, std::string owner, double balance);
    
        //function to deposit
        void deposit(double amount);
    
        //function to withdraw
        void withdraw(double amount);
    
        //function will display acount info: current owner and current balance
        void displayInfo();
    
        //fucntion that will change ownder
        void newOwnder(bank& owner, std::string newOwner);
    
    };
}
#endif

Answer 1

每个c++程序都需要一个全局main函数来运行程序。

// bank.hpp

namespace bank_hw
{
    class bank
    {
        public:
            int accountNumber;
    
        public:
            //default constructor
            bank();
    
    };
}

在另一个.cpp文件中定义您的类成员函数

// bank.cpp


using namespace bank_hw;

bank::bank(): accountNumber( 0 ) {}

和#include header .hpp文件，在其中运行main函数。

#include "bank.hpp"

int main() {
    
    bank_hw::bank b;
    
    return 0;
}