C++返回相对于某个日期的第几周

#include <iostream>
#include <boost/date_time.hpp>
using namespace std;
using namespace boost::gregorian;
//返回dtLastDatetime相对于dtCurDatetime日期的第几周
int GetOrderWeek(const date &dtLastDatetime, const date &dtCurDatetime);

void main()
{

int order = 100;
order += 200;
date myCurDatetime = from_undelimited_string("20130603122520");
date myLastDatetime = from_undelimited_string("20130602124255");

int nResult = GetOrderWeek(myLastDatetime, myCurDatetime);
cout << nResult << endl;
// cout << order << endl;

int wait;
cin >> wait;
}

int GetOrderWeek(const date &dtLastDatetime, const date &dtCurDatetime)
{
int ndtLastDatetimeDays = 0;
int ndtCurDatetimeDays = 0;
ndtLastDatetimeDays = dtLastDatetime.day_of_year();
ndtCurDatetimeDays = dtCurDatetime.day_of_year();

int nCurWeek = dtCurDatetime.day_of_week(); //表示当前交易记录平仓日期是星期几

int increase =0; //表示增量，用于计算dtLastDatetime相对于dtCurDatetime的第几个星期
if (nCurWeek = 0) //nCurWeek =0, 表示当前为星期日
{
increase = 7 - 7;
}
else
{

increase = 7 - nCurWeek;
}

int nGapName = 0; //表示dtCurDatetime与dtLastDatetime相隔多少天
nGapName = ndtCurDatetimeDays - ndtLastDatetimeDays;

int orderWeek = 0; //表示dtLastDatetime 相对于dtCurDatetime的第几周
orderWeek = (nGapName + increase) / 7;
return orderWeek;
}