#include <iostream>

#include <cmath>

#include <cstring>

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const double cdMinimumPrice =0;

const double cdMaximumPrice =70;

​

using namespace std;

​

class CFuzzyFunction

{

protected :

    double dLeft, dRight;

    char   cType;

    char*  sName;

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public:

    CFuzzyFunction(){};

    virtual ~CFuzzyFunction(){ delete [] sName; sName=NULL;}

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    virtual void

    setInterval(double l,

                double r)

    {dLeft=l; dRight=r;}

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        virtual void

    setMiddle( double dL=0,

               double dR=0)=0;

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    virtual void

    setType(char c)

    { cType=c;}

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    virtual void

    setName(const char* s)

    { 

      sName = new char[strlen(s)+1];

      strcpy(sName,s);

    }

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    bool

    isDotInInterval(double t)

    {

        if((t>=dLeft)&&(t<=dRight)) return true; else return false;

    }

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    char getType(void)const{ return cType;}

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        void 

        getName() const

    {

        cout<<sName<<endl;

    }

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    virtual double getValue(double t)=0;

};

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class CTriangle : public CFuzzyFunction

{

private: 

    double dMiddle;

​

public:

    void

    setMiddle(double dL, double dR)

    {

        dMiddle=dL;

    }

​

    double 

    getValue(double t)

    {

        if(t<=dLeft)

            return 0;

        else if(t<dMiddle)

            return (t-dLeft)/(dMiddle-dLeft);

        else if(t==dMiddle)

            return 1.0;

        else if(t<dRight)

            return (dRight-t)/(dRight-dMiddle);

        else

            return 0;

    }

};

​

class CTrapezoid : public CFuzzyFunction

{

private:

    double dLeftMiddle, dRightMiddle;

​

public:

    void

    setMiddle(double dL, double dR) 

    {

        dLeftMiddle=dL; dRightMiddle=dR;

    }

​

    double 

    getValue(double t)

    {

        if(t<=dLeft)

           return 0;

        else if(t<dLeftMiddle)

            return (t-dLeft)/(dLeftMiddle-dLeft);

        else if(t<=dRightMiddle)

            return 1.0;

        else if(t<dRight)

            return (dRight-t)/(dRight-dRightMiddle);

        else 

            return 0;

    }   

};

​

int

main(void)

{

    CFuzzyFunction *FuzzySet[3];

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    FuzzySet[0] = new CTrapezoid;

    FuzzySet[1] = new CTriangle;

    FuzzySet[2] = new CTrapezoid;

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    FuzzySet[0]->setInterval(-5,30);

    FuzzySet[0]->setMiddle(0,20);

    FuzzySet[0]->setType('r');

    FuzzySet[0]->setName("low_price");

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    FuzzySet[1]->setInterval(25,45);

    FuzzySet[1]->setMiddle(35,35);

    FuzzySet[1]->setType('t');

    FuzzySet[1]->setName("good_price");

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    FuzzySet[2]->setInterval(40,75);

    FuzzySet[2]->setMiddle(50,70);

    FuzzySet[2]->setType('r');

    FuzzySet[2]->setName("to_expensive");

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    double dValue;

    do

    {

      cout<<"\nImput the value->"; cin>>dValue;

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      if(dValue<cdMinimumPrice) continue;

      if(dValue>cdMaximumPrice) continue;

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      for(int i=0; i<3; i++)

      {

         cout<<"\nThe dot="<<dValue<<endl;

         if(FuzzySet[i]->isDotInInterval(dValue))

             cout<<"In the interval";

         else

             cout<<"Not in the interval";

         cout<<endl;

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         cout<<"The name of function is"<<endl;

         FuzzySet[i]->getName();

         cout<<"and the membership is=";

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         cout<<FuzzySet[i]->getValue(dValue);

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      }

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    }

    while(true);

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    return EXIT_SUCCESS;

}