没有用于调用构造函数的匹配函数 (c++)

no matching functions for call to constructor (c++)

提问by Tee-Man

EDIT

编辑

Ok, I've done a bit of reading again for a few hours and I think I finally understand c++ OOP a bit better (at least the basics). I decided to rewrite the entire program and code a bit at a time and test more. I think i narrowed the errors i bit more this time.

好的，我又读了几个小时，我想我终于对 C++ OOP 有了更好的理解（至少是基础知识）。我决定重写整个程序并一次编写一点代码并进行更多测试。我想这次我缩小了我的错误。

NamedStorm.h

命名风暴.h

#include <string>
#include <iostream>

#ifndef NAMEDSTORM_H_INCLUDED
#define NAMEDSTORM_H_INCLUDED

// NEVER use using namespce in header, use std instead.

class NamedStorm{
private:
    std::string stormName;
    std::string stormCategory;
    double maxWindSpeed;
    double stormPressure;
    static int stormCount;
public:

    // Constructor
    NamedStorm(std::string, double, std::string, double);
    NamedStorm(std::string);

    // Destructor
    ~NamedStorm();

    // Get functions
    int getStormCount();
    double getStormPressure();
    double getWindSpeed();
    std::string getStormCategory();
    std::string getName();

    // Set functions
    static void displayOutput();
    static void sortByNames();
    static void sortByWindSpeed();
    static void getAverageWindSpeed();
    static void getAverageStormPressure();
};

#endif // NAMEDSTORM_H_INCLUDED

NamedStorm.cpp

命名风暴.cpp

// CPP => Function definition
#include <string>

#include "NamedStorm.h"

using namespace std;

// Defining static variables
int NamedStorm::stormCount = 0;

// Constructor definition
NamedStorm::NamedStorm(std::string sName, double wSpeed, std::string sCat, double sPress){
    stormName = sName;
    windSpeed = wSpeed;
    stormCategory = sCat;
    stormPressure = sPress;
    stormCount++;
}

NamedStorm::NamedStorm(std::string sName){
    stormName = sName;
    stormCount++;
}

// Destructor definition
NamedStorm::~NamedStorm(){}

// Get (Accessor) function definition
int NamedStorm::getStormCount(){
    return stormCount;
}

double NamedStorm::getStormPressure(){
    return stormPressure;
}

string NamedStorm::getStormCategory(){
    return stormCategory;
}

string NamedStorm::getName(){
    return stormName;
}

// Set (Mutator) function definition
void NamedStorm::displayOutput(){}
void NamedStorm::sortByNames(){}
void NamedStorm::getAverageStormPressure(){}
void NamedStorm::getAverageWindSpeed(){}
void NamedStorm::getWindSpeed(){}

main.cpp

主程序

#include <iostream>
#include <string>

#include "NamedStorm.h"

using namespace std;

NamedStorm storm[5]; // Error occurs here

int main(){
   // NamedStorm Chris("Chris", 70.0, "T.S", 990.0); 
   // storm[0] = Chris;
    return 0;
}

回答by podkova

1. Remove constructor definition

1. 移除构造函数定义

In your header file (NamedStorm.h) you have definedthe default constructor of NamedStorm:

在您的头文件 ( NamedStorm.h) 中，您已经定义了 NamedStorm 的默认构造函数：

NamedStorm(){};

But what you really wanted is just the constructor declaration:

但你真正想要的只是构造函数声明：

NamedStorm();

The difference between definition and declaration is that the declaration only tells the compiler that there is some function (for example: NamedStorm constructor), whereas the definition provides the full body of this function.

定义和声明的区别在于，声明只告诉编译器存在某个函数（例如：NamedStorm 构造函数），而定义提供了该函数的完整主体。

Note that, if you specify only the declaration for your function, and forget to make the definition, you will get the undefined referencelinker error.

请注意，如果您只为函数指定声明，而忘记进行定义，则会出现undefined reference链接器错误。

Further reading: http://www.cprogramming.com/declare_vs_define.html

进一步阅读：http: //www.cprogramming.com/declare_vs_define.html

2. Correct the second constructor

2.修正第二个构造函数

NamedStorm::NamedStorm(string sName, double wSpeed, string sName, double sPress)

This can't work, because you try to pass two arguments with the same name. I guess you wanted to name the second one sCat, since you use such variable in the constructor definition. Correct version:

这行不通，因为您尝试传递两个同名的参数。我猜你想命名第二个sCat，因为你在构造函数定义中使用了这样的变量。正确版本：

NamedStorm::NamedStorm(string sName, double wSpeed, string sCat, double sPress)

3. The operator<<

3.运算符<<

If you read the first section, then you should know what's wrong with the operator<<by now. You provided only the declaration, not the definition.

如果你阅读了第一部分，那么你现在应该知道有什么问题了operator<<。您只提供了声明，而不是定义。

You can fill it like this:

你可以这样填写：

std::ostream& operator<<(ostream& out, NamedStorm& namedStorm)
{
    out << namedStorm.getName();
    return out;
}

Note that the declaration is also changed - the function now takes NamedStorm&instead of const NamedStorm&, because the getNamemethod is not declared as const. You can read about constmethods here.

请注意，声明也已更改 - 函数现在采用NamedStorm&代替const NamedStorm&，因为该getName方法未声明为const。您可以在此处阅读有关const方法的信息。

4. Define static clas variables

4.定义静态类变量

Every static variable you declare in your class (only int stormCountin your case) have to be defined. Put this line into your NamedStorm.cppfile:

您在类中声明的每个静态变量（仅int stormCount在您的情况下）都必须定义。将此行放入NamedStorm.cpp文件中：

int NamedStorm::stormCount = 0;

---

---

After applying these changes your code should work fine. However, there are still many language nuances that you could read about to improve your code. Some of them are:

应用这些更改后，您的代码应该可以正常工作。但是，您仍然可以阅读许多语言细微差别以改进您的代码。他们之中有一些是：

1. Passing function arguments as values vs const references

1. 将函数参数作为值与常量引用传递

Good read here: Is it better in C++ to pass by value or pass by constant reference?

好读在这里：在 C++ 中是按值传递还是按常量引用传递更好？

2. Functions returning object copies vs const references

2. 函数返回对象副本 vs const 引用

This question also has a nice answer on SO: Is it more efficient to return a const reference

这个问题在 SO 上也有一个很好的答案：返回常量引用是否更有效

3. Be careful with "using namespace"

3.小心“使用命名空间”

Again, SO: Why is "using namespace std" considered bad practice?

同样，SO：为什么“使用命名空间 std”被认为是不好的做法？

If you reallywant to use it, neveruse it in the header file, because it will affect all files that include it.

如果你真的要使用它，千万不要在头文件中使用它，因为它会影响所有包含它的文件。