java-一些需要注意的问题

public class Dome03 {
    public static void main(String[] args) {
        //二进制0b 八进制0 十六进制0x
        int i = 10;
        int i2 = 010;
        int i3 = 0x10;
        System.out.println(i);
        System.out.println(i2);
        System.out.println(i3);
        System.out.println("=======================");
        //浮点数舍入误差 大约 接近但不等于
        float f = 0.1f;//0.1
        double d = 1.0/10;//0.1
        System.out.println(f==d);//false
        float d1 = 123234567456.12345f;
        float d2 = d1+1;
        System.out.println(d1==d2);//true
        //结论：尽量避免使用浮点数进行比较！！！
        //银行业务使用bigdecimal类
        System.out.println("===============================");
        //=====================
        //字符拓展
        //======================
        char c1 = 'A';
        char c2 = '唐';
        System.out.println(c1);
        System.out.println((int)c1);
        System.out.println(c2);
        System.out.println((int)c2);
        char c3 = '\u0061';
        System.out.println(c3);
    }
}