Given a (decimal - e g 3.72) number that is passed in as a string,return the binary representation that is passed in as a string.If the number can not be represented accurately in binary, print “ERROR”
Example
n = 3.72, return ERROR
n = 3.5, return 11.1
For int part, similar approach of extracting numbers from int:
1. use %2 to get each digit from lowest bit to highest bit.
2. int right shift 1 position (=>>1).
3. construct the binary number (always add to the higher position of the current binary number)
Please refer to the code below for the process above.
For decimal part, use *2 approach. For example:
int n = 0.75
n*2 = 1.5
Therefore, the first digit of binary number after '.' is 1 (i.e. 0.1). After constructed the first digit, n= n*2-1
1 public class Solution {
2 /**
3 *@param n: Given a decimal number that is passed in as a string
4 *@return: A string
5 */
6 public String binaryRepresentation(String n) {
7 int intPart = Integer.parseInt(n.substring(0, n.indexOf('.')));
8 double decPart = Double.parseDouble(n.substring(n.indexOf('.')));
9 String intstr = "";
10 String decstr = "";
11
12 if (intPart == 0) intstr += '0';
13 while (intPart > 0) {
14 int c = intPart % 2;
15 intstr = c + intstr;
16 intPart = intPart / 2;
17 }
18
19 while (decPart > 0.0) {
20 if (decstr.length() > 32) return "ERROR";
21 double r = decPart * 2;
22 if (r >= 1.0) {
23 decstr += '1';
24 decPart = r - 1.0;
25 }
26 else {
27 decstr += '0';
28 decPart = r;
29 }
30 }
31 return decstr.length() > 0? intstr + "." + decstr : intstr;
32 }
33 }
这道题还有一些细节要处理，我之前忽略了
比如：