使用带有类的重载函数，无法弄清楚垃圾来自哪里

Question

我正在开发这个程序，在该程序中，用户可以输入日期数字或月份和日期来获取另一个。

我遇到的问题是，当创建一个类的实例并将其传递给构造函数时，它正确显示了日期 #，但是当它调用 print 时，我得到了垃圾。如果我将 day 初始化为 0，它会说 day 是 182，但是当调用 print 时，它会打印 0。

它在 DayOfYear() 上完美运行，但不是 DayOfYear(int day)。

我被难住了。

#include <iostream>
#include <iomanip>

using namespace std;





//class declaration
class DayOfYear
{
private:

    static const int MonthDays[];
    static const string MonthName[];
public:
    //static const int MonthDays[];
    //static const string MonthName[];
    int day;

    DayOfYear();
    DayOfYear(int day);
    DayOfYear(string month_, int day_);
    void print();   
};

DayOfYear::DayOfYear()
{
    cout << "\nEnter a number you would like to convert into a month and day: ";
    cin >> day;

    //Error check for negative numbers and numbers higher than one year
    while(day <= 0 || day > 365)
    {
        cout << "You must enter a valid number (1 thru 365)" << endl;
        cin>>day;
    }

    //call print() function
    print();
}





DayOfYear::DayOfYear(int day)
{
    cout<<"\nDay of the year"<<day<<"is";
    print();

}    

DayOfYear::DayOfYear(string month_,int day_)
{
    int count=0;

    while (month_ != DayOfYear::MonthName[count])
    {count++;}

    int result = DayOfYear::MonthDays[count] + day_;

    cout<<"Day number= "<<result<<endl;
}


//days of each month into an array
const int DayOfYear::MonthDays[] = {31, 28, 31,30,31,30,31,31,30,31,30,31};
//name of each month into an array
const string DayOfYear::MonthName[] = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};






void DayOfYear::print()
{
    int month = 0;
    //int day_=0;
    //day_=day;
    cout<<"\nprint start day: "<<day<<endl;
    while ((DayOfYear::MonthDays[month] < day)&& (month<11)){
        day=day-DayOfYear::MonthDays[month];
        month++;
    cout<<"/nprint month: "<<month<<" day: "<<day<<endl;
    }
    cout << DayOfYear::MonthName[month] << " " << day;
};


int main()
{   
    int day=0;

    DayOfYear();
    DayOfYear halfway(365/2);
    //halfway.print();


    return 0;

}

Answer 1

您需要在 DayOfYear::DayOfYear(int) 构造函数中初始化 day 成员。更改此行：

DayOfYear::DayOfYear(int day)

到这里：

DayOfYear::DayOfYear(int day_) : day(day_)

Answer 2

在你的 DayOfYear(int day) 构造函数中你永远不会分配你的私有变量，我会做这样的事情

DayOfYear::DayOfYear(int inDay)
{
    day = inDay;
    cout<<"\nDay of the year"<<day<<"is";
    print();

}