怎么用C语言编程任给一个年月日它是星期几

#include <stdio.h>
#include <string.h>
#include <time.h>
/*
Convert from MSDN

*/
void main( void )
{
struct tm *newtime;

time_t long_time;

time( &long_time ); /* Get time as long integer. */
newtime = gmtime( &long_time );

newtime->tm_mday = 11;
newtime->tm_mon = 11;
newtime->tm_year = 105;
printf("put day(1-31):\n");
scanf("%d",&newtime->tm_mday);
printf("put month(1-12):\n");
scanf("%d",&newtime->tm_mon );
newtime->tm_mon = newtime->tm_mon-1;
printf("put year(1971-2030):\n");
scanf("%d",&newtime->tm_year );
newtime->tm_year -= 1900;
mktime( newtime );
printf("This Day is %s \n it is",asctime( newtime ));
switch(newtime->tm