c++ - How to write a tester for a program that writes one bit at a time? -

i trying write tester following program see if functions correctly, however, i'm not sure if implemented flush() correctly , reason don't output. can suggest code test class see if implemented flush , writebit correctly?

#ifndef bitoutputstream_hpp #define bitoutputstream_hpp #include <iostream>  class bitoutputstream {  private:    char buf;             // 1 byte buffer of bits   int nbits;            // how many bits have been written buf   std::ostream& out;    // reference output stream use  public:   /* initialize bitoutputstream     * use given ostream output.     * */   bitoutputstream(std::ostream& os) : out(os) {     buf = nbits = 0;    // clear buffer , bit counter   }    /* send buffer output, , clear */   void flush() {   out.put(buf);   // edit: removed flush(); stop infinite recursion   buf = nbits = 0;   }     /* write least sig bit of arg buffer */   int writebit(int i) {   // if bit buffer full, flush it.   if (nbits == 8)      flush();  // write least significant bit of  // buffer @ current index. // buf = buf << 1;  option considering // buf |= 1 & i;    decided go 1 below    int lb = & 1;      // extract lowest bit   buf |= lb << nbits;  // shift nbits , put in in buf    // increment index   nbits++;    return nbits;   } };  #endif // bitoutputstream_hpp 

what wrote tester is:

#include "bitoutputstream.hpp" #include <iostream>  int main(int argc, char* argv[]) {   bitoutputstream bos(std::cout);  // channel output 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);    // prints 'a' ;)    return 0; } 

i know wrong since no output , have no way see if implementation correct. appreciate input can provide.

i compiled code with: g++ -std=c++11 main.cpp biooutputstream.hpp bitinputstream.cpp , ran with: ./a.out

1. you're never calling bitoutputstream::flush() - add call bos.flush(); following calls writebit().
2. your flush() method recursive - calls itself, result in infinite loop. remove call flush() within definition of flush().
3. your test won't print because single bit equate ascii value 1, isn't printable. try adding few more bits. e.g. writebit(1); writebit(0); writebit(0); writebit(0); writebit(0); writebit(0); writebit(1); should print a.