在 C++ 中出现很长的“不匹配 'operator+'”错误答案

【问题标题】：Getting very long "No match for 'operator+'" error in C++在 C++ 中出现很长的“不匹配 'operator+'”错误
【发布时间】：2014-05-16 05:19:54
【问题描述】：

我没有练习过 C++，正在为我正在学习的课程编写“银行”课程。每次我尝试编译我的 Bank.cpp 文件时都会收到一个很长的错误。我怀疑我在这里遗漏了一些非常明显的东西，但我不知道是什么，因为这个错误对我来说没有任何意义。

这是我正在编写的无法编译的 cpp 文件：

#include <iostream>

#include "Bank.h"

Bank::Bank(): savings(0), checking(0) { }

Bank::Bank(double savings_amount, double checking_amount): savings(savings_amount), checking(checking_amount) { }

void Bank::deposit(double amount, string account)
{
        if (account == "S") {
                savings = savings + amount;
        } else {
                checking += amount;
        }
}

void Bank::withdraw(double amount, string account)
{
        if (account == "S") {
                savings -= amount;
        } else {
                checking -= amount;
        }
}

void Bank::transfer(double amount, string account)
{
        if (account == "S") {
                savings -= amount;
                checking += amount;
        } else {
            checking -= amount;
        }
}

void Bank::transfer(double amount, string account)
{
        if (account == "S") {
                savings -= amount;
                checking += amount;
        } else {
                checking -= amount;
                savings += amount;
        }
}

void Bank::print_balances()
{
        cout << "Savings: $ " << savings;
        cout << "Checking: $ " << checking;
}

这是头文件：

#ifndef BANK_H
#define BANK_H

#include <string>

#include "Account.h"

using namespace std;

class Bank {
private:
    Account savings;
    Account checking;
public:
    Bank();
    Bank(double savings_amount, double checking_amount);
    void deposit(double amount, string account);
    void withdraw(double amount, string account);
    void transfer(double amount, string account);
    void print_balances();
};

#endif

这是顶部引用的“Account.h”头文件：

#ifndef ACCOUNT_H
#define ACCOUNT_H


class Account {
private:
    double balance;
    double interest_rate;
public:
    Account();
    Account(double amount, double rate);
    void deposit(double);
    bool withdraw(double);
    double query();
    void set_interest_rate(double rate);
    double get_interest_rate();
    void add_interest();
};

#endif

这是我收到的神秘错误：

Bank.cpp：在成员函数‘void Bank::deposit(double, std::string)’中： Bank.cpp:17: 错误: '((Bank*)this)->Bank::savings + amount' 中的'operator+' 不匹配 Bank.cpp:19: 错误: '((Bank*)this)->Bank::checking += amount' 中的'operator+=' 不匹配 Bank.cpp：在成员函数“void Bank::withdraw(double, std::string)”中： Bank.cpp:26: 错误: '((Bank*)this)->Bank::savings -= amount' 中的'operator-=' 不匹配 Bank.cpp:28: 错误: '((Bank*)this)->Bank::checking -= amount' 中的'operator-=' 不匹配 Bank.cpp：在成员函数‘void Bank::transfer(double, std::string)’中： Bank.cpp:35: 错误: '((Bank*)this)->Bank::savings -= amount' 中的'operator-=' 不匹配 Bank.cpp:36: 错误: '((Bank*)this)->Bank::checking += amount' 中的'operator+=' 不匹配 Bank.cpp:38: 错误: '((Bank*)this)->Bank::checking -= amount' 中的'operator-=' 不匹配 Bank.cpp:39: 错误: '((Bank*)this)->Bank::savings += amount' 中的'operator+=' 不匹配 Bank.cpp：在成员函数“void Bank::print_balances()”中： Bank.cpp:45：错误：'std::operator&)(& std::cout) 中的 'operatorBank::savings' /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:108：注意：候选人是：std::basic_ostream <_chart _traits>& std::basic_ostream<_chart _traits>::operator& ()(std::basic_ostream<_chart _traits>&)) [ _CharT = char, _Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:117：注意：std::basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator& ()(std::basic_ios<_chart _traits>&)) [with _CharT = 字符，_Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:127：注意：std::basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator)(std::ios_base&)) [with _CharT = char, _Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:165：注意：std::basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator) [with _CharT = char, _Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/ostream.tcc:119：注意：std:: basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator) [with _CharT = char, _Traits = std::char_traits] Bank.cpp:46: 错误: 'std::operator&)(& std::cout) 中的 'operator)"检查：$")) Bank::checking' /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:108：注意：候选人是：std::basic_ostream <_chart _traits>& std::basic_ostream<_chart _traits>::operator& ()(std::basic_ostream<_chart _traits>&)) [ _CharT = char, _Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:117：注意：std::basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator& ()(std::basic_ios<_chart _traits>&)) [with _CharT = 字符，_Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:127：注意：std::basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator)(std::ios_base&)) [with _CharT = char, _Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:165：注意：std::basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator) [with _CharT = char, _Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/ostream.tcc:119：注意：std:: basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator) [with _CharT = char, _Traits = std::char_traits] [004709613@jb359-5 Lab1]$ Bank.cpp：在成员函数‘void Bank::deposit(double, std::string)’中： -bash：意外标记附近的语法错误(' [004709613@jb359-5 Lab1]$ Bank.cpp:17: error: no match for ‘operator+’ in ‘((Bank*)this)->Bank::savings + amount’ -bash: syntax error near unexpected token(' [004709613@jb359-5 Lab1]$ Bank.cpp:19: error: no match for ‘operator+=’ in ‘((Bank)this)->Bank::checking += amount’ -bash：意外标记附近的语法错误(' [004709613@jb359-5 Lab1]$ Bank.cpp: In member function ‘void Bank::withdraw(double, std::string)’: -bash: syntax error near unexpected token(' [004709613@jb359-5 Lab1]$ Bank.cpp:26: error: no match for ‘operator-=’ in ‘((Bank*)this)->Bank::savings -= amount’ -bash：意外标记附近的语法错误(' [004709613@jb359-5 Lab1]$ Bank.cpp:28: error: no match for ‘operator-=’ in ‘((Bank*)this)->Bank::checking -= amount’ -bash: syntax error near unexpected token(' [004709613@jb359-5 Lab1]$ Bank.cpp：在成员函数‘void Bank::transfer(double, std::string)’中： -bash：意外标记附近的语法错误(' [004709613@jb359-5 Lab1]$ Bank.cpp:35: error: no match for ‘operator-=’ in ‘((Bank*)this)->Bank::savings -= amount’ -bash: syntax error near unexpected token(' [004709613@jb359-5 Lab1]$ Bank.cpp:36: error: no match for ‘operator+=’ in ‘((Bank*)this)->Bank::checking += amount’ -bash：意外标记附近的语法错误(' [004709613@jb359-5 Lab1]$ Bank.cpp:38: error: no match for ‘operator-=’ in ‘((Bank*)this)->Bank::checking -= amount’ -bash: syntax error near unexpected token(' [004709613@jb359-5 Lab1]$ Bank.cpp:39: error: no match for ‘operator+=’ in ‘((Bank*)this)->Bank::savings += amount’ -bash：意外标记附近的语法错误(' [004709613@jb359-5 Lab1]$ Bank.cpp: In member function ‘void Bank::print_balances()’: -bash: syntax error near unexpected token(' [004709613@jb359-5 Lab1]$ Bank.cpp:45: error: no match for 'operator &)(& std::cout)), ((const char*)"Savings: $")) Bank::savings' /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:108：注意：候选人是：std::basic_ostream <_chart _traits>& std::basic_ostream<_chart _traits>::operator& ()(std::basic_ostream<_chart _traits>&)) [ _CharT = char, _Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:117：注意：std::basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator& ()(std::basic_ios<_chart _traits>&)) [with _CharT = 字符，_Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:127：注意：std::basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator)(std::ios_base&)) [with _CharT = char, _Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:165：注意：std::basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator) [with _CharT = char, _Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/ostream.tcc:119：注意：std:: basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator) [with _CharT = char, _Traits = std::char_traits] Bank.cpp:46: 错误: 'std::operator&)(& std::cout) 中的 'operator)"检查：$")) Bank::checking' /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:108：注意：候选人是：std::basic_ostream <_chart _traits>& std::basic_ostream<_chart _traits>::operator& ()(std::basic_ostream<_chart _traits>&)) [ _CharT = char, _Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:117：注意：std::basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator& ()(std::basic_ios<_chart _traits>&)) [with _CharT = 字符，_Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:127：注意：std::basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator)(std::ios_base&)) [with _CharT = char, _Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/ostream:165：注意：std::basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator& std::basic_ostream<_chart _traits>::operator) [with _CharT = char, _Traits = std::char_traits] /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/ostream.tcc:119：注意：std:: basic_ostream<_chart _traits>& std::basic_ostream<_chart _traits>::operator*) [with _CharT = char, _Traits = std::char_traits]

有人知道我做错了什么吗？我敢肯定这是非常愚蠢的事情。我也可以发布头文件，但是由于远程编辑问题，很难这样做。

【问题讨论】：

savings 和 checking 的任何类型都不支持这样的算术或输出。
请贴出头文件，让我们看看savings是什么类型
你需要为 operator+ 添加一个成员函数，它说明你想要它做什么。
重申一下：储蓄和支票有哪些类型？ Bank.cpp 第 17 行是空白的，您确定您发布的代码正是您尝试编译的代码吗？
储蓄和支票的类型是Account，这是我写的另一个类，编译得很好。我觉得我在这里做的事情很明显是错误的。此外，Bank.cpp 文件中的第 17 行实际上是我在此处发布的代码中的第 12 行。我删除了我课程所需的文件顶部的一些 cmets。很抱歉造成混乱。

标签： c++

【解决方案1】：

我怀疑您将保存和检查私有成员声明为“帐户”而不是双重。即使这是您的预期设计，您也无法在没有明确定义 operator+(const Account &) 的情况下添加用户定义的类对象。

【讨论】：

【解决方案2】：

您需要为 Account 类定义 + 运算符，以便它知道要做什么。由于您尝试使用双精度添加 Account 对象，因此您需要这个。

double Account::operator+(const double value) const {
    return balance + value;
}

如果你想添加两个帐户对象，你可以用这个重载。

Account Account::operator+(const Account &other) const {
    return Account(balance + other.balance, interest_rate);
}

【讨论】：

Account 没有接受单个 double 作为输入的构造函数或 = 运算符，因此第一个运算符不会像您显示的那样编译，因为结果被分配给Accountm 所以它需要一个 Account 结果。在第二个运算符中，不要使用new，我建议使用this.interest_rate 而不是0。
是的，在我发布它之后才意识到。现在应该修好了。用 Java 编写了这么多代码，以至于我不假思索地输入了 new。

【解决方案3】：

在您的源代码的这一行中：

            savings = savings + amount;

savings 的类型是 Account，但 amount 是 double。除非您在 Account 类上定义 + 成员运算符，例如

Account operator+(const double value) const;

或全局+ 运算符（可能是friend 函数）之类的

Account operator+(const Account& account, const double value);

那么你不能做这样的添加。

【讨论】：

【解决方案4】：

如果您不想在类中添加额外的运算符，那么不要编写：

savings = savings + amount;

使用 Account 类已经声明的方法并编写：

savings.deposit(amount);

【讨论】：