In computing, a bit is a 0 or 1 value. We define a bit string to be a possibly empty string which consists of bits. Example bit strings are: • "0" • "1" • "01" • "0000" • "111111111" • "1101010010110"...

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Extracted text: In computing, a bit is a 0 or 1 value. We define a bit string to be a possibly empty string which consists of bits. Example bit strings are: • "0" • "1" • "01" • "0000" • "111111111" • "1101010010110" Given a bit string, it is natural to want to count the number of 0 bits or the number of 1 bits in the string. Assume we wish to count the number of 1 bits. For the example strings, the counts would be: • "0" → 0 • "1" → 1 • "01" → 1 • "0000" → 0 "111111111" 9 "1101010010110" 7


Extracted text: Counting the number of 1 bits in a bit string s can be accomplished in Java by first initializing an integer counter n to 0. Next, we implement a loop which iterates over each character c of s and when c is '1' we add 1 to n. When c is '0' we do nothing. Here is the implementation of that algorithm: private int countOnes(String s) { int n = 0; for (int i = 0; i < s.length();="" ++i)="" {="" if="" (s.charat(i)="=" '1')="" {="" ++n;="" }="" return="" n;="" this="" problem="" is="" also="" amenable="" to="" being="" solved="" using="" a="" recursive="" method="" rather="" than="" an="" iterative="" method="" (one="" that="" employs="" a="" loop).="" your="" job="" is="" to="" select="" the="" correct="" pieces="" of="" code="" from="" those="" available="" and="" arrange="" them="" in="" proper="" order="" to="" implement="" a="" recursive="" method="" with="" the="" same="" method="" signature.="" private="" int="" countones(string="" s)="" {="" [line1]="" [line2]="" [line3]="" [line4]="" [line5]="" [line6]="" [line7]="" [line8]="">