关于map在头文件中的问题

[Jason_Yao]

有一个线性回归程序

#pragma   warning   (disable:4786)

//#include "RegressionLine.hpp"
#include <map>
#include <string>
#include <iostream>
#include <math.h>


using namespace std;



class RegressionLine
{
    public:
        typedef map<double,double> Points;
        RegressionLine(Points & points);
        virtual ~RegressionLine();

        const double slope() const;
        const double yIntercept() const;
        const double regressionCoefficient() const;
    
    private:

        double slope_;
        double yIntercept_;
        double regressionCoefficient_;
    
};
// 上面是定义一个类，如果把它作为一个头文件，放在.hpp文件中的话，编译就会出现很多错误。而把typedef拿出来后，把这段代码贴到.cpp文件
// 的前面的话，程序就能运行了，请问这是为什么啊？

RegressionLine::RegressionLine(Points & points)
{
    int n = points.size();
    if (n < 2)
        throw (string("Must have at least two points"));


    double sumx=0,sumy=0,sumx2=0,sumy2=0,sumxy=0;
    double sxx,syy,sxy;

    // Conpute some things we need 
    map<double, double>::const_iterator i;
    for (i = points.begin(); i != points.end(); i++)
    {
        double x = i->first;
        double y = i->second;

        sumx += x;
        sumy += y;
        sumx2 += (x * x);
        sumy2 += (y * y);
        sumxy += (x * y);
    }
    sxx = sumx2 - (sumx * sumx / n);
    syy = sumy2 - (sumy * sumy / n);
    sxy = sumxy - (sumx * sumy / n);

    // Infinite slope_, non existant yIntercept
    if (abs(sxx) == 0)
        throw (string("Inifinite Slope"));

    // Calculate the slope_ and yIntercept
    slope_ = sxy / sxx;
    yIntercept_ = sumy / n - slope_ * sumx / n;

    // Compute the regression coefficient
    if (abs(syy) == 0)
        regressionCoefficient_ = 1;
    else
        regressionCoefficient_ = sxy / sqrt(sxx * syy);
}

RegressionLine::~RegressionLine()
{
}

const double RegressionLine::slope() const
{
    return slope_;
}

const double RegressionLine::yIntercept() const
{
    return yIntercept_;
}

const double RegressionLine::regressionCoefficient() const
{
    return regressionCoefficient_;
}


int main()
{
    const int count = 10;
    double times[count] = { 
        -0.20707, 0.706672, 1.63739, 2.03117, 3.31874, 
        5.38201, 6.79971, 6.31814, 8.20829, 8.53994 };
    double water[count] = { 
        -0.319029, 0.0931669, 2.17286, 2.76818, 3.56743, 
        4.11772, 5.52709, 7.46613, 8.7654, 9.58096 };

    Points pnts;

    for (int i = 0; i < count; i++)
    {
        pnts[times[i]] = water[i];
    }

    RegressionLine myLine(pnts);

    cout << "Slope = " << myLine.slope() << endl;
    cout << "yIntercept = " << myLine.yIntercept() << endl;
    cout << "Regression Coefficient = "<< myLine.regressionCoefficient() << endl;

	return 0;
}

[baihacker]

RegressionLine::Points

如果放在里面,应该像上面这样使用这个Points

[lzr4304061988012]

int main()
{...
RegressionLine::Points pnts;
...
}

[xhs_lh04]

RegressionLine::Points pnts;
应该这样用吧,因为是类里的一个typedef

或者你把
typedef map<double,double> Points;
移到类外面试试,那样肯定可以

[liumingrong]

你的typedef map<double,double> Points;是在类RegressionLine作用域内，
在外面使用就得RegressionLine::Points,或者把它拿出来

[chaojiew]

，放在.hpp文件中的话，编译就会出现很多错误

什么错误？

[Jason_Yao]

一到四楼的方法，本来的程序就是这么写的。但是运行不通，编译出来20几个错误。主要是说point没定义，还有说头文件出现了不认识的“<”之类的。
我的编译环境是vc++6.0
谢谢各位

[太乙]

#pragma   warning   (disable:4786)

//#include "RegressionLine.hpp"
#include <map>
#include <string>
#include <iostream>
#include <math.h>


using namespace std;



class RegressionLine
{
    public:
        typedef map<double,double> Points;
        RegressionLine(Points & points);
        virtual ~RegressionLine();

        const double slope() const;
        const double yIntercept() const;
        const double regressionCoefficient() const;
    
    private:

        double slope_;
        double yIntercept_;
        double regressionCoefficient_;
    
};
// 上面是定义一个类，如果把它作为一个头文件，放在.hpp文件中的话，编译就会出现很多错误。而把typedef拿出来后，把这段代码贴到.cpp文件
// 的前面的话，程序就能运行了，请问这是为什么啊？

RegressionLine::RegressionLine(Points & points)
{
    int n = points.size();
    if (n < 2)
        throw (string("Must have at least two points"));


    double sumx=0,sumy=0,sumx2=0,sumy2=0,sumxy=0;
    double sxx,syy,sxy;

    // Conpute some things we need 
    map<double, double>::const_iterator i;
    for (i = points.begin(); i != points.end(); i++)
    {
        double x = i->first;
        double y = i->second;

        sumx += x;
        sumy += y;
        sumx2 += (x * x);
        sumy2 += (y * y);
        sumxy += (x * y);
    }
    sxx = sumx2 - (sumx * sumx / n);
    syy = sumy2 - (sumy * sumy / n);
    sxy = sumxy - (sumx * sumy / n);

    // Infinite slope_, non existant yIntercept
    if (abs(sxx) == 0)
        throw (string("Inifinite Slope"));

    // Calculate the slope_ and yIntercept
    slope_ = sxy / sxx;
    yIntercept_ = sumy / n - slope_ * sumx / n;

    // Compute the regression coefficient
    if (abs(syy) == 0)
        regressionCoefficient_ = 1;
    else
        regressionCoefficient_ = sxy / sqrt(sxx * syy);
}

RegressionLine::~RegressionLine()
{
}

const double RegressionLine::slope() const
{
    return slope_;
}

const double RegressionLine::yIntercept() const
{
    return yIntercept_;
}

const double RegressionLine::regressionCoefficient() const
{
    return regressionCoefficient_;
}


int main()
{
    const int count = 10;
    double times[count] = { 
        -0.20707, 0.706672, 1.63739, 2.03117, 3.31874, 
        5.38201, 6.79971, 6.31814, 8.20829, 8.53994 };
    double water[count] = { 
        -0.319029, 0.0931669, 2.17286, 2.76818, 3.56743, 
        4.11772, 5.52709, 7.46613, 8.7654, 9.58096 };

		RegressionLine::Points pnts;

    for (int i = 0; i < count; i++)
    {
        pnts[times[i]] = water[i];
    }

    RegressionLine myLine(pnts);

    cout << "Slope = " << myLine.slope() << endl;
    cout << "yIntercept = " << myLine.yIntercept() << endl;
    cout << "Regression Coefficient = "<< myLine.regressionCoefficient() << endl;

    return 0;
}


以上代码在vc6.0和mingw下都能通过：

运行结果：

vc6.0：

Slope = 1.04116
yIntercept = -0.0754263
Regression Coefficient = 0.966565
Press any key to continue


mingw下：

Slope = 1.04116
yIntercept = -0.0754263
Regression Coefficient = 0.966565


Terminated with return code 0
Press any key to continue ...

[Jason_Yao]

回7楼的朋友：
你的程序确实可以运行。但是当我把前面的类定义单独放到一个.hpp文件中的时候就不行了，出现了13个错误：

d:\ctest\linear_regression\regressionline.hpp(12) : error C2143: syntax error : missing ';' before '<'
d:\ctest\linear_regression\regressionline.hpp(12) : error C2059: syntax error : '<'
d:\ctest\linear_regression\regressionline.hpp(12) : error C2238: unexpected token(s) preceding ';'
d:\ctest\linear_regression\regressionline.hpp(13) : error C2629: unexpected 'class RegressionLine ('
d:\ctest\linear_regression\regressionline.hpp(13) : error C2238: unexpected token(s) preceding ';'
d:\ctest\linear_regression\regressionline.cpp(33) : error C2065: 'Points' : undeclared identifier
d:\ctest\linear_regression\regressionline.cpp(33) : error C2065: 'points' : undeclared identifier
d:\ctest\linear_regression\regressionline.cpp(34) : error C2448: '<Unknown>' : function-style initializer appears to be a function definition
d:\ctest\linear_regression\regressionline.cpp(105) : error C2039: 'Points' : is not a member of 'RegressionLine'
        d:\ctest\linear_regression\regressionline.hpp(10) : see declaration of 'RegressionLine'
d:\ctest\linear_regression\regressionline.cpp(105) : error C2146: syntax error : missing ';' before identifier 'pnts'
d:\ctest\linear_regression\regressionline.cpp(105) : error C2065: 'pnts' : undeclared identifier
d:\ctest\linear_regression\regressionline.cpp(109) : error C2109: subscript requires array or pointer type
d:\ctest\linear_regression\regressionline.cpp(109) : error C2106: '=' : left operand must be l-value
Error executing cl.exe.

请问这是什么问题啊？谢谢

[liuhao159753]

你放在.h文件中时，在main函数中用到那个类时，需要先声明下那个类吧，然后才可以用，或是像7楼那样 RegressionLine::Points pnts;
来用。
总觉得你这提示出的错误，都是某个细节出问题了。我是新手，拙见。

[mimengdelei]

#include <map>
#include <string>
#include <iostream>
#include <math.h>
using namespace std;

放到单独.hpp上面的几行加了吗?
你的错误提示都是类型未声明之类的。