Java Reference
In-Depth Information
static String toAlignedBinaryString(int i, int numBits)
String result = Integer.toBinaryString(i);
if (result.length() > numBits)
return null; // cannot fit result into numBits
int numLeadingZeros = numBits-result.length();
String zerosPrefix = "";
for (int j = 0; j < numLeadingZeros; j++)
zerosPrefix += "0";
return zerosPrefix+result;
The toAlignedBinaryString() method takes two arguments: the first argu-
ment specifies the 32-bit integer that is to be converted into a binary string, and the
second argument specifies the number of bit columns in which to fit the string.
After calling toBinaryString() to return i 's equivalent binary string without
leading zeros, toAlignedBinaryString() verifies that the string's digits can fit
into the number of bit columns specified by numBits . If they do not fit, this method
returnsnull.(Youwilllearnabout length() andother String methodslaterinthis
Movingon, toAlignedBinaryString() calculatesthenumberofleading "0" s
toprependto result ,andthenusesaforlooptocreateastringofleadingzeros.This
method ends by returning the leading zeros string prepended to the result string.
Althoughusingthecompoundstringconcatenationwithassignmentoperator( += )in
alooptobuildastringlooksokay,itisveryinefficientbecauseintermediate String
I can contrast it with the more efficient code that I present later in this chapter.
When you run this application, it generates the following output:
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