g++没有匹配的函数调用错误 [英] g++ no matching function call error

问题描述

我遇到了编译器错误，但我不知道为什么.

I've got a compiler error but I can't figure out why.

.hpp:

#ifndef _CGERADE_HPP
#define _CGERADE_HPP
#include "CVektor.hpp"
#include <string>

class CGerade
{

protected:
    CVektor o, rv;

public:

    CGerade(CVektor n_o, CVektor n_rv);

    CVektor getPoint(float t);

    string toString();
};

.cpp:

#include "CGerade.hpp"

CGerade::CGerade(CVektor n_o, CVektor n_rv)
{
    o = n_o;
    rv = n_rv.getUnitVector();
}

错误信息:

CGerade.cpp:10: error: no matching function for call to ‘CVektor::CVektor()’
CVektor.hpp:28: note: candidates are: CVektor::CVektor(float, float, float)
CVektor.hpp:26: note:                 CVektor::CVektor(bool, float, float, float)
CVektor.hpp:16: note:                 CVektor::CVektor(const CVektor&)
CGerade.cpp:10: error: no matching function for call to ‘CVektor::CVektor()’
CVektor.hpp:28: note: candidates are: CVektor::CVektor(float, float, float)
CVektor.hpp:26: note:                 CVektor::CVektor(bool, float, float, float)
CVektor.hpp:16: note:                 CVektor::CVektor(const CVektor&)

推荐答案

从外观上看，你的 CVektor 类没有默认构造函数，CGerade 在你的构造函数:

From the looks of it, your CVektor class has no default constructor, which CGerade uses in your constructor:

CGerade::CGerade(CVektor n_o, CVektor n_rv)
{ // <-- by here, all members are constructed
    o = n_o;
    rv = n_rv.getUnitVector();
}

您可以(并且可能应该)添加一个，但更好的是使用初始化列表来初始化成员:

You could (and probably should) add one, but better is to use the initialization list to initialize members:

CGerade::CGerade(CVektor n_o, CVektor n_rv) :
o(n_o),
rv(n_rv.getUnitVector())
{}

它指定了成员的初始化方式.(在上面，它默认为不存在的默认构造函数.)

Which specifies how the members are initialized. (And above, it was defaulting to the non-existent default-constructor.)

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