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POHow to write a tester for a program that writes one bit at a time?
 

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  1. POHow to write a tester for a program that writes one bit at a time?
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    <p>I am trying to write a tester for the following program to see if it functions correctly, however, I'm not sure if I implemented flush() correctly and for some reason I don't get any output. Can someone suggest code that will test this class to see if I implemented flush and writeBit correctly? </p> <pre><code>#ifndef BITOUTPUTSTREAM_HPP #define BITOUTPUTSTREAM_HPP #include &lt;iostream&gt; class BitOutputStream { private: char buf; // one byte buffer of bits int nbits; // how many bits have been written to buf std::ostream&amp; out; // reference to the output stream to use public: /* Initialize a BitOutputStream that will * use the given ostream for output. * */ BitOutputStream(std::ostream&amp; os) : out(os) { buf = nbits = 0; // clear buffer and bit counter } /* Send the buffer to the output, and clear it */ void flush() { out.put(buf); // EDIT: removed flush(); to stop the infinite recursion buf = nbits = 0; } /* Write the least sig bit of arg into buffer */ int writeBit(int i) { // If bit buffer is full, flush it. if (nbits == 8) flush(); // Write the least significant bit of i into // the buffer at the current index. // buf = buf &lt;&lt; 1; this is another option I was considering // buf |= 1 &amp; i; but decided to go with the one below int lb = i &amp; 1; // extract the lowest bit buf |= lb &lt;&lt; nbits; // shift it nbits and put in in buf // increment index nbits++; return nbits; } }; #endif // BITOUTPUTSTREAM_HPP </code></pre> <p>What I wrote as a tester is:</p> <pre><code>#include "BitOutputStream.hpp" #include &lt;iostream&gt; int main(int argc, char* argv[]) { BitOutputStream bos(std::cout); // channel output to stdout bos.writeBit(1); // Edit: added lines below bos.writeBit(0); bos.writeBit(0); bos.writeBit(0); bos.writeBit(0); bos.writeBit(0); bos.writeBit(0); bos.writeBit(1); // now prints an 'A' ;) return 0; } </code></pre> <p>I know this is wrong since I get no output and have no way to see if the implementation is correct. I appreciate any input you can provide.</p> <p>I compiled the code with: g++ -std=c++11 main.cpp BioOutputStream.hpp BitInputStream.cpp and ran it with: ./a.out</p>
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    1. COYour test function never actually calls `BitOutputStream::flush()`.
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      1. POHow to write a tester for a program that writes one bit at a time?
      1. USJonathan Potter
    2. COHow can I fix that? I tried BitOutputStream::flush() but still got no output.
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      1. USNapalidon
    3. COAdd a call to `bos.flush();` after your call to `writeBit()`.
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      1. POHow to write a tester for a program that writes one bit at a time?
      1. USJonathan Potter
 

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