itest.java

java编程思想第四版习题答案

// object/ITest.java
// TIJ4 Chapter Object, Exercise 7, page 90
// Turn the Incrementable code fragments into a working program.

class StaticTest {
	static int i = 47;
}
class Incrementable {
	static void increment() { StaticTest.i++; }
}
public class ITest {
	public static void main(String[] args) {
	System.out.println("StaticTest.i= " + StaticTest.i);
	StaticTest st1 = new StaticTest();
	StaticTest st2 = new StaticTest();
	System.out.println("st1.i= " + st1.i);
	System.out.println("st2.i= " + st2.i);
	Incrementable sf = new Incrementable();
	sf.increment();
	System.out.println("After sf.increment() called: ");
	System.out.println("st1.i = " + st1.i);
	System.out.println("st2.i = " + st2.i);
	Incrementable.increment();
	System.out.println("After Incrementable.increment called: ");
	System.out.println("st1.i = " + st1.i);
	System.out.println("st2.i = " + st2.i);
	}
}