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| 5. 2. 1. 使用构造函数 |
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- Every class must have at least one constructor.
- If there is no constructors for your class, the compiler will supply a default constructor(no-arg constructor).
- A constructor is used to construct an object.
- A constructor looks like a method and is sometimes called a constructor method.
- A constructor never returns a value
- A constructor always has the same name as the class.
- A constructor may have zero argument, in which case it is called a no-argument (or no-arg, for short) constructor.
- Constructor arguments can be used to initialize the fields in the object.
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The syntax for a constructor is as follows. |
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constructorName (listOfArguments) {
[constructor body]
}
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public class MainClass {
double radius;
// Class constructor
MainClass(double theRadius) {
radius = theRadius;
}
}
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