26．#includevoid main( ){int year=2015,month=2;switch(month){case 2: if(year%4= =0&&year%100!=0||year%400= =0) printf(″day=29\n″);case 4:case 6:case 9:case 11: printf(″day=30\n″);break;default: printf″day=31\n″);}}