Java从零开始学五(数据类型转换)

分为“自动类型转换”和“强制类型转换”

低级别------》高级别

        byte b=7;        int i=b;        System.out.PRintln("i= "+i);        double d=i;        System.out.println("d= "+d);        double dw=5+5.6*4+'A';        System.out.println("dw="+dw);        

结果：

i= 7d= 7.0dw=92.4

高级别---》低级别，可能会导致数据丢失

在变量前加小括号来转换，(类型)变量

         double d = 3.6;        int i =(int) d;        System.out.println("i= "+i);        int x=786;        short sh = (short)x;        System.out.println("sh="+sh);        byte b = (byte)x;        System.out.println("b= "+b);

结果:

i= 3sh=786b= 18

         double d =84.54;        int c= (int)d/2;        System.out.println(c);

结果:42

        String str = "Hello";        int x = 30;        str=str+x;        System.out.println("str= "+str);

结果:

str= Hello30

        int i =1;        int j=2;        System.out.println("1+2= "+1+2);

结果:

1+2= 12