1
2 // Copyright Nat Goodspeed 2013.
3 // Distributed under the Boost Software License, Version 1.0.
4 // (See accompanying file LICENSE_1_0.txt or copy at
5 // http://www.boost.org/LICENSE_1_0.txt)
6
7 #include <iostream>
8 #include <iomanip>
9 #include <vector>
10 #include <string>
11 #include <utility>
12
13 #include <boost/coroutine2/all.hpp>
14
15 struct FinalEOL{
~FinalEOLFinalEOL16 ~FinalEOL(){
17 std::cout << std::endl;
18 }
19 };
20
main(int argc,char * argv[])21 int main(int argc,char* argv[]){
22 using std::begin;
23 using std::end;
24 std::vector<std::string> words{
25 "peas", "porridge", "hot", "peas",
26 "porridge", "cold", "peas", "porridge",
27 "in", "the", "pot", "nine",
28 "days", "old" };
29 int num=5,width=15;
30 boost::coroutines2::coroutine<std::string>::push_type writer(
31 [&](boost::coroutines2::coroutine<std::string>::pull_type& in){
32 // finish the last line when we leave by whatever means
33 FinalEOL eol;
34 // pull values from upstream, lay them out 'num' to a line
35 for (;;){
36 for(int i=0;i<num;++i){
37 // when we exhaust the input, stop
38 if(!in) return;
39 std::cout << std::setw(width) << in.get();
40 // now that we've handled this item, advance to next
41 in();
42 }
43 // after 'num' items, line break
44 std::cout << std::endl;
45 }
46 });
47 std::copy(begin(words),end(words),begin(writer));
48 std::cout << "\nDone";
49 return EXIT_SUCCESS;
50 }
51