列出本年度所有星期天的日期

这题与《列出本月所有星期天的日期》有点相似，稍微变动一下，即可完成。

      
   public IEnumerable<DateTime> AllSundaysInYear( 
   int year) 
   
    { 
   
        System.Globalization.CultureInfo ci =  
   new System.Globalization.CultureInfo( 
   " 
   en-US 
   "); 
   
         
   for ( 
   int m =  
   1; m <=  
   12; m++) 
   
        { 
   
             
   int days = ci.Calendar.GetDaysInMonth(year, m); 
   
 
   
             
   for ( 
   int i =  
   1; i <= days; i++) 
   
            { 
   
                 
   if ( 
   new DateTime(year, m, i).DayOfWeek == DayOfWeek.Sunday) 
   
                     
   yield  
   return  
   new DateTime(year, m, i); 
   
            } 
   
        } 
   
    }