未正确检查日期结构

Question

我有一些 C++ 代码：

#include <bjarne/std_lib_facilities.h>

struct Date {
    int month;
    int day;
    int year;
};

Date get_date();
Date get_birth_date();
int days_in_month (int month);
bool is_valid_date (const Date& date);
bool is_before (const Date& date1, const Date& date2);

int main()
{
    cout << "Welcome to Age Calculator!\n"; 
    Date current;
    current = get_date();
    cout << "Would you like to see how old you are (y/n)?";
    char answer, slash;
    cin >> answer;
    Date birthday;
    if(answer == 'y'){
        birthday = get_birth_date();
        bool valid = is_valid_date (birthday);
        bool before = is_before (current,birthday);
        while(!valid && !before){
            cout << "Invalid birth date?  Please re-enter: ";
            cin >> birthday.month >> slash >> birthday.day >> slash >> birthday.year;
            valid = is_valid_date (birthday);
            before = is_before (current,birthday);
        }
        cout << "Your birthday is: " << birthday.month << "/" << birthday.day << "/" << birthday.year << "\n";
    }
    else
    cout << "You are so chicken! \n";    
}

Date get_date()
{
    cout << "Please enter today's date (mm/dd/yyyy): ";
    Date today; 
    char slash;
    cin >> today.month >> slash >> today.day >> slash >> today.year;
    bool valid = is_valid_date (today);
    while(!valid){
        cout << "Invalid date?  Please re-enter: ";
        cin >> today.month >> slash >> today.day >> slash >> today.year;
        valid = is_valid_date (today);
    }
    cout << "Date entered was: " << today.month << "/" << today.day << "/" << today.year << "\n";
    return today;
}

Date get_birth_date()
{
    cout << "Please enter your birth date (mm/dd/yyyy): ";
    Date birth; 
    char slash;
    cin >> birth.month >> slash >> birth.day >> slash >> birth.year;
    return birth;
}

int days_in_month (int month)
{
    int month31[7] = {1,3,5,7,8,10,12};
    for(int i = 0; i < 7; i++){
        if(month == month31[i])
            return 31;
    }
    int month30[4] = {4,6,9,11};
    for(int i = 0; i < 4; i++){
        if(month == month30[i])
            return 30;
    }
    if(month == 2)
        return 28;
}

bool is_valid_date (const Date& date)
{
    int months[12] = {1,2,3,4,5,6,7,8,9,10,11,12};
    int days = 0; 
    for(int i = 0; i < 12; i++){
        if(date.month == months[i]){
            days = days_in_month (date.month);
            if(date.day <= days && date.day > 1){
                return true;
            }

    }
    return false;
}

bool is_before (const Date& date1, const Date& date2)
{
    cout << date1.day << " " << date2.day; 
    if(date2.year < date1.year){
        return true;
    }
    else if(date2.year == date1.year)
    {
        cout << "-";
        if(date2.month < date1.month)
            return true;
        else if(date2.month == date1.month){
            if(date2.day <= date1.day)
                return true;
        }
        else
            return false;

    }
    return false;
}

我知道 is_valid_date 函数有效，但是当我测试在当前日期进入之后的生日时，由于某种原因，它通过了is_before 测试并且永远不会进入要求用户输入有效生日的 while 循环。任何建议将不胜感激！提前致谢！

编辑：我正在测试的具体输入是：对于今天的日期，我输入 05/06/2015，对于生日，我输入 05/07/2015。然后它打印生日，这意味着它跳过了 int main() 中的 while 循环，这是它不应该做的，因为生日在当前日期之后。

Answer 1

你的条件有误：

while(!valid && !before)

如果输入的生日无效并且晚于当前日期，您的条件会尝试获取新的生日。我想你想要：

while(!valid || !before)

如果输入的生日无效或晚于当前日期

Answer 2

您应该将 while(!valid && !before) 更改为 while(!valid || !before)。

只要出生日期无效或出生日期晚于当前日期，您就想留在循环中。目前，如果您输入一个在当前日期之后的有效日期，它将跳出循环，因为第一个条件为假（日期有效）。

未正确检查日期结构

Date Struct is not properly being checked

c++

struct

boolean

while-loop