1. Nonsense perhaps you have already heard disputes goto statement, goto know that in Java, is still a reserved keyword, but are not allowed. Let's look at the classic use goto:
1: statement1;
2: statement_label_for_section2:
3: statement2;
4: goto statement_label_for_section2;
You can see 2: statement_label_for_section2: a code fragment (Section) of the opening tag.
Java language does not allow use of goto, but you can use as 2: statement_label_for_section2: the same code fragment labeled as break / continue the jump target.
See documents related standards: <> 14.7 Labeled Statements
2. Application of nested loops, I sometimes need to jump from outside the inner loop in the loop. Labeled Statements can be used to facilitate the achievement.
1: for (int I1 = 0; I1 <10; I1 + +) (
2: loop1:
3: for (int I2 = 0; I2 <20; I1 + +) (
4: break loop1;
5:)
6:)
continue to use and the use of break is the same.
Java language is not widely used in many small ideas. See: <>
3.Blocks
<> 14.2 Blocks
Perhaps you are a slacker like me. Among the special code in the Test Case, I often need to define a lot of the same Method object, these objects are similar in major operations, you should know what I was thinking: Copy & Past. And for each object from a different name can be a pain to do. At the same time these objects are often only short-lived Ghost.
1: import java.util.ArrayList;
2: import java.util.Collection;
3:
4: public class T2 (
5:
6: public static void main (String [] args) (
7: (
8: Collection c = new ArrayList ();
9: c.add ("1");
10: c.clear ();
11:)
12: (
13: Collection c = new ArrayList ();
14: c.add ("2");
15: c.clear ();
16:)
17:)
18:
19:)
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