c语言实现简单日历intdayNum(intyear,intmonth){if(month==2){if(judgeYear(year)==0)return29;elsereturn28;}else{switch(month){case1:return31;break;case3:return31;break;case4:return30;break;case5:return31;break;case6:return30;break;case7:return31;break;case8:return31;break;c