.NET Framework的DateTime型别本身就有转Day,Hour,Minute等Method，所以要转十分方便。但C/C++呢?
C/C++的<time.h>(<ctime>)提供了localtime()，可将sec一次转成所要的信息，该struct定义如下 1 
struct tm 
{ 2
int tm_sec; // sec. 3 int tm_min; // min. 4 int tm_hour; // hour 5 int tm_mday; // day 6 int tm_mon; // month 7 int tm_year; // year 8 int tm_wday; // day of week 9 int tm_yday; // day of year10 int tm_isdst; // 夏令时间 11
}
以下为localtime()的范例程序 struct tm { 2 int tm_sec; // sec. 3 int tm_min; // min. 4 int tm_hour; // hour 5 int tm_mday; // day 6 int tm_mon; // month 7 int tm_year; // year 8 int tm_wday; // day of week 9 int tm_yday; // day of year10 int tm_isdst; // 夏令时间 11} 1 /**/ /* 2(C) OOMusou 2006 http://oomusou.cnblogs.com 3 4Filename : localtime.cpp 5Compiler : Visual C++ 8.0 6Description : Demo how to use localtime() to get min part & hour part 7Release : 11/26/2006 8*/ 9 
#include < iostream > 10 #include < ctime > 11 12 // Time-wasting function 13 void foo(); 14 // Get specified floating point number from double 15 int getDigitFromDouble( double , int ); 16 17 int main() { 18 clock_t t1 = clock();19 // Time-wasting function20 foo();21 clock_t t2 = clock();2223 // Total sec., but including floating part, not only integer24 double sec = (double)(t2 - t1) / CLOCKS_PER_SEC;25 // 0.1 sec. part26 int ssec = getDigitFromDouble(sec,1);27 // Convert dobule to const time_t, 28 // Since localtime needs (const time_t*) parameter29 const time_t time_t_sec = (time_t)sec;30 // localtime() return (struct *tm)31 struct tm* ts = localtime(&time_t_sec);3233 std::cout << "Total sec:" << sec << std::endl;34 std::cout << "min:" << ts->tm_min << std::endl;35 std::cout << "sec:" << ts->tm_sec << std::endl;36 std::cout << "0.1 sec:" << ssec << std::endl;3738 return 0;39} 40 41 void foo() { 42 for(int i = 0; i != 1000000; ++i) 43 for(int j = 0; j != 100000; ++j);44} 45 46 // get specified floating point number from double 47 int getDigitFromDouble( double d, int n) { 48 int t = 1;49
for(int j = 0; j != n-1; ++j) { 50 t *= 10;51
}5253 d = d * t;54 int i = (int)d;5556 return (int)((double)(d-i)*10);57}
本范例为了抓到0.1秒，所以才用了clock()，一般若只想抓到sec.，用time()即可。 See Also Reference C程序设计 500个应用范例技巧大全集 P.473, 平田 丰 着/ 黄正凯 译, 博硕文化 /**/ /* 2(C) OOMusou 2006 http://oomusou.cnblogs.com 3 4Filename : localtime.cpp 5Compiler : Visual C++ 8.0 6Description : Demo how to use localtime() to get min part & hour part 7Release : 11/26/2006 8*/ 9 #include < iostream > 10 #include < ctime > 11 12 // Time-wasting function 13 void foo(); 14 // Get specified floating point number from double 15 int getDigitFromDouble( double , int ); 16 17 int main() { 18 clock_t t1 = clock();19 // Time-wasting function20 foo();21 clock_t t2 = clock();2223 // Total sec., but including floating part, not only integer24 double sec = (double)(t2 - t1) / CLOCKS_PER_SEC;25 // 0.1 sec. part26 int ssec = getDigitFromDouble(sec,1);27 // Convert dobule to const time_t, 28 // Since localtime needs (const time_t*) parameter29 const time_t time_t_sec = (time_t)sec;30 // localtime() return (struct *tm)31 struct tm* ts = localtime(&time_t_sec);3233 std::cout << "Total sec:" << sec << std::endl;34 std::cout << "min:" << ts->tm_min << std::endl;35 std::cout << "sec:" << ts->tm_sec << std::endl;36 std::cout << "0.1 sec:" << ssec << std::endl;3738 return 0;39} 40 41 void foo() { 42 for(int i = 0; i != 1000000; ++i) 43 for(int j = 0; j != 100000; ++j);44} 45 46 // get specified floating point number from double 47 int getDigitFromDouble( double d, int n) { 48 int t = 1;49 for(int j = 0; j != n-1; ++j) { 50 t *= 10;51 }5253 d = d * t;54 int i = (int)d;5556 return (int)((double)(d-i)*10);57}