随机时间.cpp

C++源代码集

#include <iostream.h>
#include <iomanip.h>
#include <math.h>

const double PI=4*atan(1);
const double INIT_SEED=0.123456789;

void showPosInt(int nVal,char cTrail)
{
    //exit if nVal is not positive or zero
	if(nVal<0)
		return;

	if(nVal<10)
		cout << '0' << nVal;
	else
		cout << nVal;

	if(cTrail !='\0')
		cout << cTrail;
	else
		cout << endl;
}

void showTime(int nHour,int nMinute,int nSecond)
{
    showPosInt(nHour,':');
	showPosInt(nMinute,':');
	showPosInt(nSecond,'\0');
}

class RandomTime1
{
public:
	RandomTime1()
	{m_fSeed=INIT_SEED;}
	void getTime(int &nHour,int &nMinute,int &nSecond);

protected:
	double m_fSeed;

	virtual int random(int nMax);
	double sqr(double x)
	{return x * x;}
	double frac(double x)
	{return x-long(x);}
};

class RandomTime2:public RandomTime1
{
public:
	RandomTime2():RandomTime1(){}

protected:
	virtual int random(int nMax);
	double cube(double x)
	{return x * x * x;}
};

class RandomTime3:public RandomTime2
{
public:
	RandomTime3():RandomTime2(){}

protected:
	virtual int random(int nMax);
	double fourth(double x)
	{return sqr(x) * sqr(x);}
};

void RandomTime1::getTime(int &nHour,int &nMinute,int &nSecond)
{
    nHour=random(24);
    nMinute=random(60);
    nSecond=random(60);
}

int RandomTime1::random(int nMax)
{
    m_fSeed=nMax * frac(sqr(PI + m_fSeed));
	return int(m_fSeed);
}

int RandomTime2::random(int nMax)
{
    m_fSeed=nMax * frac(cube(PI + m_fSeed));
	return int(m_fSeed);
}

int RandomTime3::random(int nMax)
{
    m_fSeed=nMax * frac(fourth(PI + m_fSeed));
	return int(m_fSeed);
}

main()
{
    const int MAX=5;

	int nHour,nMinute,nSecond;
	RandomTime1 RT1;
	RandomTime2 RT2;
	RandomTime3 RT3;

	cout << " Sequence of time generated by "
		<< " instance of class RandomTime1 is: " << endl;
	for(int i=0;i<MAX;i++)
	{
	    RT1.getTime(nHour,nMinute,nSecond);
		showTime(nHour,nMinute,nSecond);
	}

	cout << endl;
	cout << " Sequence of time generated bu "
		<< " instance of class RandomTime2 is: " << endl;
	for(i=0;i<MAX;i++)
	{
	    RT2.getTime(nHour,nMinute,nSecond);
		showTime(nHour,nMinute,nSecond);
	}
	cout << endl;
	cout << " Sequence of time generated bu "
		<< " instance of class RandomTime3 is: " << endl;
	for(i=0;i<MAX;i++)
	{
	    RT3.getTime(nHour,nMinute,nSecond);
		showTime(nHour,nMinute,nSecond);
	}
	return 0;
}