变量

 

　　　　//整型
        byte b = 127;//-128~127
        short s = 1;//-32768~32767
        int it = 214700000;//-21亿4748万3648~21亿4748万3647
        long l = 90000000000l;//-9223372036854775808~9223372036854775807
        
        System.out.println(b);
        System.out.println(s);
        System.out.println(it);
        System.out.println(l);
        
        int i = 55;// 十进制
        int i2 = 0x37;// 十六进制
        int i3 = 067;// 八进制
        int i4 = 0b00110111;// 二进制
        System.out.println(i);
        System.out.println(i2);
        System.out.println(i3);
        System.out.println(i4);
            
        double d=1.23e2;
        System.out.println(d);
        float f = 3.14f;
        double d1 = 3.14;//默认为double类型
        double d2 = 3.14e2;//3.14乘以10的2次方
        System.out.println(f);
        System.out.println(d1);
        System.out.println(d2);
        
        //转义字符
        System.out.println("\"");
        System.out.println("\'");
        System.out.println("\\");
        
        short s1 = 1;
        short s2 = 2;
        short s3 = (short) (s1+s2);
        System.out.println(s3);
        
        //命名规则数字不能作为第一个，符号只能用$和_
        String _1_ ="---";
        System.out.println(_1_);