Crazy Java Learning Notes Object-oriented (iii)-method property and value passing

The ownership of the method:
From a syntactic point of view: methods must be defined in a class

The method either belongs to the class itself (static adornment) or to an instance-- is it a class or an object? with or without static modification

When calling a method: Must have a keynote object (subject, caller)

1  Public class mathtest{2      Public Static void Main (string[] args) {3         System.out.println (Math.sin (1.57)); 4         System.out.println (Math.sin (MATH.PI/2)); 5     }6 }

1  Public classTestMethod {2 String name;3 4     //When you customize a constructor with parameters, the system no longer provides a parameterless constructor for the class5     //Note: If the programmer does not have a constructor, the system will provide a non-parametric constructor for the class by default6      PublicTestMethod (String name) {7          This. Name =name;8     }9         Ten      Public voidWalk () { OneSystem.out.println ( This. Name + "Walking"); A     } -  -      Public voidrun () { the         //TestMethod t = new TestMethod ("Old A"); -         //T.walk (); -         //method does not see the this represents who, who calls it on behalf of WHO, here is the TT call run, so this represents the TT -          This. Walk (); +System.out.println ( This. Name + "in running"); -     } +  A      Public Static voidMain (string[] args) { atTestMethod TT =NewTestMethod ("Old C"); - Tt.run ();  -     } -}

Method Value Delivery:

　The parameter passing mechanism of the Java method :"value pass/Copy Pass", which does not pass the value of the method in the past, but is passed in the form of a copy.

　　method of variable number of parameters:Type ... Formal parameter name

1 classTestargs {2      Public voidAgeintAge ) {3System.out.println ("A's age is:" +Age );4     }5 6     //int ... represents a parameter that can pass in multiple int types7      Public voidTestint... ages) {8         //in this method, ages is equivalent to an array9          for(intag:ages) {TenSystem.out.println ("B's age is:" +AG); One         } A     } -  -      Public Static voidMain (string[] args) { the         //define a TA variable to point to the Testargs instance, because the methods in the class are instance methods, so you must create an instance to invoke -Testargs TA =NewTestargs (); -Ta.age (22); -System.out.println ("~~~~~~~~~~~~~~~~~~~~~"); +Ta.test (10,20,11,23,55,19,44,68); -     } +}

Attention:

A, each method can have at most one parameter with a variable number of parameters public void Test (int ... nums,string ... name) x
B, parameters with variable number must be in the last
public void Test (int ... nums,string name) x
public void Test (String name,int ... nums) √

Crazy Java Learning Notes Object-oriented (iii)-method property and value passing