为什么我的计算崩溃了

我实际上已经完成了此程序。我猜我唯一的问题是我的计算。我的数字完全不在。我是新的，无法发布图像，所以这是我输出的链接。示例：http：//imageshack.us/photo/my-images/62/16902078.jpg/

numdays.h

#ifndef NUMDAYS_H
#define NUMDAYS_H
#include <iostream>
#include <math.h>
using namespace std;
class NumDays
{
private:
    double hours, days;
    void calcDays();
public:
    // Constructors
    NumDays();
    NumDays(double);
    // Mutator Functions
    void setHours(double);
    // Accessor Functions
    double getHours();
    double getDays();
    // Overloaded operator functions
    NumDays operator + (const NumDays &);   // Overloaded +
    NumDays operator - (const NumDays &);   // Overloaded -
    NumDays operator ++ ();                 // Overloaded Prefix ++
    NumDays operator ++ (int);              // Overloaded Postfix ++
    NumDays operator -- ();                 // Overloaded Prefix --
    NumDays operator -- (int);              // Overloaded Postfix --
};
#endif

numdays.cpp

// Implementation file for the NumDays class
#include <iostream>
#include <math.h>
#include "NumDays.h"
using namespace std;
// Recalculation function
void NumDays::calcDays()
{
    days = hours / 8;
}
// Default Constructor
NumDays::NumDays()
{
    hours = 0;
    days = 0;
}
// Constructor 1
NumDays::NumDays(double h)
{
    hours = h;         
    days = hours * 1 / 8;   
}

// Mutatory Functions
void NumDays::setHours(double h)
{
    hours = h;
}

// Accessor Functions
double NumDays::getHours()
{
    return hours;
}
double NumDays::getDays()
{
    NumDays::calcDays();
    return days;
}

// Overloaded operator functions
NumDays NumDays::operator + (const NumDays &a)
{
    NumDays temp;
    temp.hours = this->hours + a.hours;
return temp;
}
NumDays NumDays::operator - (const NumDays &a)
{
    NumDays temp;
    temp.hours = this->hours + a.hours;
    return temp;
}

NumDays NumDays::operator ++ ()
{
    ++hours;
    calcDays();
    return *this;
}
NumDays NumDays::operator -- ()
{
    --hours;
    calcDays();
    return *this;
}
NumDays NumDays::operator ++ (int)
{
    NumDays temp(*this);
    ++hours;
    return temp;
}
NumDays NumDays::operator -- (int)
{
    hours--;
    calcDays();
    return *this;
}

main.cpp

#include <iostream>
#include "NumDays.h"
using namespace std;
int main()
{
    double hours1, hours2;
    //Prompt for the data for the first 2 objects
    cout << "Enter the number of hours for the the object called One: ";
    cin >> hours1;
    cout << "Enter the number of hours for the the object called Two: ";
    cin >> hours2;
    // Define two objects of WorkHours
    NumDays one(hours1), two(hours2);
    cout << "One: " << one.getDays() << " day(s)" << endl;
    cout << "Two: " << two.getDays() << " day(s)" << endl << endl;
    // Demonstrate addition and subtraction operators
    cout << "Three = One + Two: " << (one - two).getDays() << " day(s)" << endl;
    cout << "One - Two: " << (one - two).getDays() << " day(s)" << endl << endl;
    // Define a third and fourth object to be used for further operator demonstrations
    NumDays three(one + two), four;
    // Demonstrate increment and decrement operators
    four = three++;
    cout << "Four = Three++ " << endl;
    cout << " Three: " << three.getDays() << " day(s)" << endl;
    cout << " Four: " << four.getDays() << " day(s)" << endl << endl;
    four = ++three;
    cout << "Four = ++Three: " << endl;
    cout << " Three: " << three.getDays() << " day(s)" << endl;
    cout << " Four: " << four.getDays() << " day(s)" << endl << endl;
    four = three--;
    cout << "Four = Three--: " << endl;
    cout << " Three: " << three.getDays() << " day(s)" << endl;
    cout << " Four: " << four.getDays() << " day(s)" << endl << endl;
    four = --three;
    cout << "Four = --Three: " << endl;
    cout << " Three: " << three.getDays() << " day(s)" << endl;
    cout << " Four: " << four.getDays() << " day(s)" << endl;
    system("pause");
    return 0;
}