In PL/1, an element expression that specifies a position within a dimension of an array.A subscript can also be an asterisk, in which case it specifies the entire extent of the dimension.

• 1语言中的一种元素表达式,用于指出某一数组某一维内的一个位置,下标也可以是星号,在此情况下它表示该维的整个范围。