各種表達式expression

01.乘法:
{{"總價 = " + qty * cost}}


02.字串:
{{"就讀 = " + school + "," + department}}


03.物件變數:
{{"姓名 = " + person.name + ",年紀 = " + person.age + ",電話 = " + person.tel}}


04.陣列:
輸入月份:
{{"查詢該月份的天數 = " + month[num-1] }}


05.物件陣列變數:
查詢班上第幾位同學(1~5):
{{"查詢該位同學,姓名 = " + student[no-1].name + ",電話 = " + student[no-1].tel}}