1. 记录时间

#include <atlstr.h>
#include <time.h>
clock_t clockBegin, clockEnd;
clockBegin =// do sth.= clock();
double totaltime = (double)(clockEnd-clockBegin)/CLOCKS_PER_SEC;
//输出时间是s
CString csTemp;
csTemp.Format("%f", totaltime);
OutputDebugString(csTemp);

2. 报错

error C2664: 'void ATL::CStringT<BaseType,StringTraits>::Format (...)

解决

csTemp.Format(_T("%f"), totaltime);