Software Construction笔记

3·18

主要了解了MIT中 immutable和mutable数据类型的区别。

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Primitives	Objective Reference Types
int，long, byte, short, char, float, double, boolean	Classes, interfaces, arrays, enums, annotations
No indentity except their value	Have identity distinct from value
Immutable	Some mutable, some not
On stack, exist only when in use	On heap, garbage collected
Can’t achieve unity of expression	Unity of expression with generics
Dirt cheap	More costly

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此外，也学习了mutability和immutability。迭代器Iterator，对应强调for循环

List<String> lst = ...;
for (String str : lst) {
    System.out.println(str);
}

而用迭代器的话，如下所示：

List<String> lst = ...;
Iterator iter = lst.iterator();
while (iter.hasNext()) {
  String str = iter.next();
  System.out.println(str);
}