typetrans.java

Java面向对象编程(随书配套源代码) 阐述了面向对象编程的思想

package chapter3;

public class TypeTrans 
{
	public static void main(String[] args)
	{
		byte b = 127;
		short s1 = 127;
		short s2 = 32767;
		int i = 2147483647;
		long L =  2147483648L; //long型字面常量需在数尾加“L”或"l"；
		
		float f = 12.0000001f; //实数字面常量默认为double型，定义为float型需在数尾加“F”或f;
		double d = 13.0000029601;  //默认为double型。
		
		//强制类型转换
		b = (byte)s1;
		System.out.println("short型强制转换为byte型后,b=" + b);
		b = (byte) s2;
		System.out.println("short型强制转换为byte型后,b=" + b);
		s1 = (short)i;
		System.out.println("int型强制转换为short型后,s1=" + s1);
		i = (int) L;
		System.out.println("long型强制转换为int型后,i=" + i);
		i = (int) f;
		System.out.println("float型强制转换为int型后,i=" + i);
		f = (float)d;
		System.out.println("doubble型强制转换为float型后,f=" + f);
		
		//自动类型转换
		b=127;
		s1 = 32767;
		i = b + s1; //自动将byte型和short型转换为int型；
		System.out.println("b+s1自动类型转换自动类型转换到int型后,i=" + i);
		i = 1047483647;
		L = i*2 ;
		System.out.println("int自动类型转换到long型后,L=" + L);
		f = 12.0000001f;
		d = 12.123456789;
		d = f +d ;
		System.out.println("float型自动类型转换到double型后,d=" + d);	
	}
}