Mercurial > Algorithms__Sedgewick
view algs4-c++/src/Josephus.cpp @ 17:10e1ce04c4f1
The Josephus program, ex 1.3.37
| author | Eris Caffee <discordia@eldalin.com> |
|---|---|
| date | Fri, 19 Jun 2015 18:18:47 -0500 |
| parents | |
| children |
line source
1 #include <algorithm>
2 #include <cstdlib>
3 #include <iostream>
4 #include <sstream>
6 #include "Queue.hpp"
8 void usage( char * name ) {
9 std::cerr << name << " skip size" << std::endl;
10 exit( EXIT_FAILURE );
11 }
14 int read_int( char *s ) {
15 std::stringstream ss;
17 ss.str( s );
18 int tmp;
19 ss >> tmp;
20 if ( ss.fail() ) {
21 return -1;
22 }
23 return tmp;
24 }
26 int main( int argc, char **argv ) {
28 if ( argc != 3 ) {
29 usage( argv[0] );
30 }
32 int skip = read_int( argv[1] );;
33 int size = read_int( argv[2] );
34 if ( skip == -1 || size == -1 ) {
35 usage( argv[0] );
36 }
39 Queue<int> q;
41 for ( int i = 0; i < size; ++i ) {
42 q.enqueue( i );
43 }
45 int i = 0;
46 while ( q.size() ) {
47 int tmp = q.dequeue();
48 if ( (i+1) % skip )
49 q.enqueue( tmp );
50 else
51 std::cout << tmp << std::endl;
52 ++i;
53 }
55 }