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 fractional part of the number can not be represented accurately in binary with at most 32 characters, returnERROR.
Example
For n ="3.72", return"ERROR".
For n ="3.5", return"11.1".
这是两年前一刷写的答案，完全不知道自己干嘛。嘛，2进制小数位后的转换：乘2取整
public String binaryRepresentation(String n) {
if(n==null||n.equals("")){
return "ERROR";
}
String[] splitedStr = n.split("\\.");
String frac = generateFrac(splitedStr[1]);
if(frac.equals("ERROR")){
return frac;
}
String inte = generateDec(splitedStr[0]);
if(frac.equals("")){
return inte;
}
return inte+"."+frac;
}
private String generateFrac(String fracStr){
String one = "1";
String zero = "0";
double f = Double.parseDouble("0."+fracStr);
double divisor = 1;
StringBuilder sb = new StringBuilder();
int i = 0;
while (f != 0) {
divisor = divisor/2;
if(f > divisor){
sb.append(one);
f = f - divisor;
}else if(f < divisor){
sb.append(zero);
}else{
sb.append(one);
break;
}
i++;
if (i > 31) {
break;
}
}
return i > 31 ? "ERROR" : sb.toString();
}
private String generateDec(String DecStr){
return Integer.toBinaryString(Integer.parseInt(DecStr));
}