What week is a date obtained by QT

Because the function test of the previous version appeared and 1 month 1 The same day as Monday （1-7), There will be a small week , Such as 2022 year 1 month 8 The number is identified as the first week .

The new method is changed into the following ：

ceil((start.daysTo(value) - count) /7.0) + 1;

Less than two people make up 0 Handle , Make sure the return value is in four digit week format .

QString class::getWeek(QDateTime value)
{
    int result = -1; 
    QDateTime start = QDateTime::fromString(value.toString("yyyy") + "0101", "yyyyMMdd");

    int myWeek = start.date().dayOfWeek();
    int count = 7 - myWeek;  //  If the difference exceeds this value, it will be the next week 
 

    double num = start.daysTo(value); 
    result = ceil((start.daysTo(value) - count) /7.0) + 1; 

    QString str = "";
    if(result < 10)
        str = "0" + QString::number(result);
    else
        str = result;
    str = value.toString("yy") + str;
    return str;

}

--------------------------------------------------------- Old version split line ---------------------------------------------------------

be based on QT Of QDateTime、QDate Function to get the day of the week and date interval （ Leap years are calculated by QT Call library adjustment return ）

Get the function of the week ：

//  Calculate the incoming time as the week of the year 
int class::getWeek(QDateTime value)
{
    int result = -1;    //  Return results  
    //  Get the first day of the year , Used to determine the number of days in the first week 
    QDateTime start = QDateTime::fromString(value.toString("yyyy") + "0101", "yyyyMMdd"); 

    int myWeek = start.date().dayOfWeek();    // dayOfWeek To get the day of the week （1~7）
    int count = 7 - myWeek;  //  The first week includes count+1 God  
    // daysTo Is the number of days from the call date to the parameter date （ If the parameter date is earlier than the call date, a negative number is returned ）
    double num = start.daysTo(value)/7.0;
    result = ceil(num);    // ceil Is the rounding up function  
    //  Because the first week is mostly dissatisfied 7 God , Therefore, the next week needs to determine the number of days in the first week （ Remainder ）
    if((start.daysTo(value) % 7) - count > 0)
        ++result;

    return result;

}