Mainly talk about the few blocks of Java, can't be said, because in fact, each piece can be said a lot, I will talk about the focus of these students or something should be paid. Value type: Although it is an object-oriented language, the value type is still essential, if you have mastered C calculations and conversion rules in C, then I don't think there is no problem, only two Points Need Note: 1,14.0 This floating point constant is considered to be a Double type, only plus the F suffix is a Float type; It is seen as a minimum value that can represent the number, so Byte B = 100; will not report an error. Quote: I also turn over from C / C , in fact, the so-called reference type is reflected in C , there is a reference type when passing, from C, it is a pointer, but we can't It makes hard exercises on the pointer. So the focus here is: 1. All objects in Java are generated in the heap, so things that need to be similar to pointers point to it, that is, references; 2, we will use the reference to the object to reference, in addition to assignment In addition, there should be no operation is for the reference itself, this is the difference between C's pointer and Java's reference. Class and object: This is a large piece, there are many things, not to speak, say a few points: 1, class method, class attribute and member method, member attributes are loaded, initialized, and the same; 2, In the constructor, this () and super () usage; 3, the subclass of loading process, initialization process, and construction; 4, the method of overloading and overwriting; 5, overwriting the polymorphic issues. (Note: The application of the polymorphism is in the method, the attribute does not work) the parameter passed: If the address value recorded in the reference type, it is considered to be the value of the reference type variable, then all methods of Java are called. When you use a value to pass the value type, reference type biographical address. IO stream: Compared with C, Java input and output, especially input is very troublesome, maybe because of the object-oriented consideration? do not know. Java offers a lot of IO streams, but we don't have to figure out all kinds of IOs. We only need to know what features each with the characteristics and characteristics, how the character stream is constructed on byte stream, almost all When the character stream is constructed, it is based on an existing byte stream, and its design makes we can set up the IO to one-section one section like a set of pipes until we want to Use the IO object (Example: BUFFEREDReader). When we use it later, we can check the API again. I think the few classes that mainly want to see are: FileReader, FileWriter, BufferedReader, with the System.out object, for the input of the text, it is enough Used, as for others, I don't think it's not necessary to see so much, I will see it again.
