1 //计算某一天的前一天的日期 日期格式：YYYY-MM-DD
2 bool GetTheDayBefore(const std::string &strOneDate,std::string &TheDayBefore)
3 {
4 int iYear,iMonth,iDay;
5 if (10 != strOneDate.length()) //形如xxxx-xx-xx格式的日期长度为10
6 {
7 return false;
8 }
9
10 iYear = atoi(strOneDate.substr(0,4).c_str());
11 iMonth = atoi(strOneDate.substr(5,2).c_str());
12 iDay = atoi(strOneDate.substr(8,2).c_str());
13
14 int iWeekDay = -1;
15 struct tm tTime;
16 time_t t_of_day;
17 tTime.tm_year=iYear-1900;
18 tTime.tm_mon=iMonth-1;
19 tTime.tm_mday=iDay;
20 tTime.tm_hour=0;
21 tTime.tm_min=0;
22 tTime.tm_sec=0;
23 tTime.tm_isdst=0;
24 t_of_day=mktime(&tTime);
25 localtime_s(&tTime, &t_of_day);
26
27 t_of_day = t_of_day - 24*3600;
28 localtime_s(&tTime, &t_of_day);
29 char buffer[Date_String_Size] = {0};
30 sprintf_s(buffer, Date_String_Size, "%04d-%02d-%02d", tTime.tm_year+1900, tTime.tm_mon+1, tTime.tm_mday);
31 TheDayBefore = buffer;
32
33 return true;
34 }
