对时间按指定时间段进行分组，可用于并发度计算

#include <iostream>
#include <string>
#include <sstream>
#include <vector>
using namespace std;

unsigned long long strToull(const string & a_str)
{
#if defined (WIN32)
    return strtoul(a_str.c_str(), NULL, 10);
#else
    return strtoull(a_str.c_str(), NULL, 10);
#endif
}

vector<string> getGroupList(int a_iGroup, const string &a_strStartTime, const string &a_strEndTime)
{
    time_t tStartTime = strToull(a_strStartTime.c_str());
    time_t tEndTime = strToull(a_strEndTime.c_str());

    //cout<<"begin "<<tStartTime<<" end "<<tEndTime<<endl;

    struct tm tmNow;
    tm* pTm = localtime_r(&tStartTime, &tmNow);

    struct tm *tmNew = new tm();
    *tmNew = *pTm;
    tmNew->tm_min = int(pTm->tm_min/a_iGroup) * a_iGroup; 
    tmNew->tm_sec = 0;

    char tmBuf[64];
    memset(tmBuf, 0, sizeof(tmBuf));

    strftime(tmBuf, 64, "%Y-%m-%d %H:%M:00", tmNew);

    stringstream str;
    str<<a_iGroup<<"-"<<tmBuf;

    vector<string> valuelist;
    valuelist.push_back(str.str());

    time_t tBegin = mktime(tmNew) + a_iGroup * 60;
    while(tBegin < tEndTime)
    {
        struct tm tmTime;
        localtime_r(&tBegin, &tmTime);
        memset(tmBuf, 0, sizeof(tmBuf));
        strftime(tmBuf, 64, "%Y-%m-%d %H:%M:00", &tmTime);
        
        stringstream strs;
        strs<<a_iGroup<<"-"<<tmBuf;
        valuelist.push_back(strs.str());

        tBegin += a_iGroup * 60;
    }

    return valuelist;
}

int main(int argc, char* argv[])
{
    int group = 1;
    if(argc == 2)
    {
        group = atoi(argv[1]);
    }
    else
    {
        cout<<"help:"<<endl;
        cout<<"    ./get group"<<endl;
        return 0;
    }

    vector<string> valuelist = getGroupList(group, "1472111395", "1472112495");
    for(vector<string>::iterator iter = valuelist.begin(); iter != valuelist.end(); ++iter)
    {
        cout<<"value is:"<<*iter<<endl;
    }

    return 0;
}

g++ getgrouplist.cpp -o get

输出：