c语言里面的调用显示系统时间的函数及实现过程是什么

||| #include "stdafx.h"#include <time.h>#include <stdio.h>void main( void ){ struct tm when; time_t now asctime( &when ) ); else perror( "mktime failed" );} days &days ); when.tm_mday = when.tm_mday + days; if( (result = mktime( &when )) = (time_t)-1 ) printf( "In %d days the time will be %s/n" asctime( &when ) ); printf( "How many days to look ahead: " ); scanf( "%d" result; int days; time( &now ); when = *localtime( &now ); printf( "Current time is %s/n" 直接用system（time）函数即可哦