1 | #include <fstream.hfa> // sin/sout |
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2 | #include <stdlib.hfa> // convert |
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3 | #include <string.h> |
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4 | #include <coroutine.hfa> |
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5 | |
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6 | struct Potato { |
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7 | PRNG & prng; |
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8 | unsigned int deadline; // when timer goes off |
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9 | unsigned int timer; // up counter to deadline |
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10 | }; // Potato |
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11 | |
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12 | void reset( Potato & potato, unsigned int maxTicks = 10 ); |
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13 | void ?{}( Potato & potato, PRNG & prng, unsigned int maxTicks = 10 ); |
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14 | |
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15 | void ?{}( Potato & potato, PRNG & prng, unsigned int maxTicks ) with(potato) { |
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16 | &potato.prng = &prng; |
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17 | reset( potato, maxTicks ); |
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18 | } // Potato |
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19 | |
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20 | coroutine Player { |
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21 | PRNG & prng; |
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22 | int id; // player identity |
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23 | Potato & potato; // potato being tossed |
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24 | Player * partner[2]; // left and right player |
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25 | }; // Player |
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26 | |
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27 | void ?{}( Player & player, PRNG & prng, unsigned int id, Potato & potato ) { |
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28 | &player.prng = &prng; |
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29 | player.id = id; |
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30 | &player.potato = &potato; |
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31 | } // Player |
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32 | |
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33 | Player & umpire; |
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34 | |
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35 | ExceptionDecl( Explode ); |
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36 | ExceptionDecl( Terminate, Player * victim; ); |
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37 | ExceptionDecl( Election ); |
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38 | ExceptionDecl( cmd_error ); // convert(...) throws out_of_range or invalid_argument |
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39 | |
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40 | void reset( Potato & potato, unsigned int maxTicks ) with(potato) { |
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41 | if ( maxTicks < 2 ) abort( "Hot Potato initialized with less than 2 ticks" ); // optional |
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42 | deadline = prng( prng, 1, maxTicks ); |
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43 | timer = 0; |
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44 | sout | " POTATO goes off after " | deadline | " tick" | nosep | (deadline > 1 ? "s" : ""); |
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45 | } // reset |
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46 | |
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47 | void countdown( Potato & potato ) with(potato) { |
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48 | timer += 1; |
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49 | if ( timer == deadline ) throwResume ExceptionInst( Explode ); |
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50 | } // countdown |
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51 | |
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52 | static unsigned int rightOf( unsigned int me, unsigned int total ) { |
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53 | return ( me + 1 ) % total; |
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54 | } // rightOf |
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55 | |
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56 | static unsigned int leftOf( unsigned int me, unsigned int total ) { |
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57 | return ( me + total - 1) % total; |
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58 | } // leftOf |
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59 | |
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60 | enum { LEFT = 0, RIGHT = 1 }; |
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61 | |
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62 | static void vote( Player & player ) { // cause partner to vote |
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63 | resume( player ); checked_poll(); |
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64 | } // vote |
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65 | |
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66 | static void terminate( Player & player ) { // resume umpire |
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67 | resume( player ); |
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68 | checked_poll(); |
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69 | sout | "THIS SHOULD NOT BE REACHED"; |
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70 | } // terminate |
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71 | |
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72 | void init( Player & player, Player & lp, Player & rp ) with(player) { // supply partners |
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73 | partner[LEFT] = &lp; |
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74 | partner[RIGHT] = &rp; |
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75 | resume( player ); // establish main as starter for termination |
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76 | checked_poll(); |
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77 | } // init |
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78 | |
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79 | int getId( Player & player ) { // player id |
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80 | return player.id; |
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81 | } // getId |
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82 | |
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83 | void toss( Player & player ) { // tossed the potato |
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84 | resume( player ); |
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85 | checked_poll(); |
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86 | } // toss |
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87 | |
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88 | void main( Player & player ) with(player) { |
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89 | try { |
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90 | enable_ehm(); // allow delivery of nonlocal exceptions |
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91 | suspend; // return immediately after establishing starter |
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92 | checked_poll(); |
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93 | |
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94 | for ( ;; ) { |
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95 | checked_poll(); |
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96 | if ( partner[LEFT] == &player ) { // stop when only one player |
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97 | sout | id | " wins the Match!"; |
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98 | return; |
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99 | } // exit |
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100 | |
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101 | countdown( potato ); // player is eliminated if countdown() returned true |
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102 | |
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103 | size_t side = prng( prng, 2 ); |
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104 | sout | id | " -> " | nonl; |
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105 | toss( *partner[ side ] ); // random toss left/right |
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106 | } // for |
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107 | disable_ehm(); |
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108 | } catchResume( Terminate * v ) { |
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109 | v->victim->partner[LEFT]->partner[RIGHT] = v->victim->partner[RIGHT]; // unlink node |
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110 | v->victim->partner[RIGHT]->partner[LEFT] = v->victim->partner[LEFT]; |
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111 | delete( v->victim ); |
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112 | reset( potato ); |
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113 | sout | "U " | nonl; // start new game |
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114 | flush( sout ); |
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115 | } catchResume( Election * election ) { |
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116 | sout | "election"; |
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117 | sout | " -> " | id | nonl; |
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118 | if ( id > getId( umpire ) ) &umpire = &player; // set umpire to highest id so far |
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119 | resumeAt( *partner[RIGHT], *election ); |
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120 | disable_ehm(); // disable ehm since we can't handle execption thrown in vote here and want to poll later |
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121 | vote( *partner[RIGHT] ); |
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122 | enable_ehm(); // enable after vote |
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123 | } catchResume( Explode * ) { |
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124 | sout | id | " is eliminated"; |
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125 | if ( &player == &umpire ) { |
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126 | try { |
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127 | id = -1; // remove from election |
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128 | resumeAt( *partner[RIGHT], ExceptionInst( Election ) ); |
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129 | vote( *partner[RIGHT] ); // start election |
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130 | checked_poll(); |
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131 | } catchResume( Election * election ) { |
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132 | sout | " : umpire " | getId( umpire ); |
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133 | } // try |
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134 | } // if |
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135 | resumeAt( umpire, ExceptionInst( Terminate, &player ) ); |
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136 | terminate( umpire ); |
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137 | assert( false ); // no return |
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138 | } // try |
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139 | } // main |
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140 | |
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141 | |
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142 | int main( int argc, char * argv[] ) { |
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143 | enum { |
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144 | MinNoPlayers = 2, // minimum players in the game |
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145 | MaxNoPlayers = 10, // maximum players in the game |
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146 | DefaultGames = 5, // default games to play |
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147 | }; |
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148 | intmax_t numGames = DefaultGames; // games to play |
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149 | intmax_t numPlayers = 0; // players for a particular game |
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150 | intmax_t seed = 42; // random-number seed |
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151 | bool playersSet = false; |
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152 | char * nosummary = getenv( "NOSUMMARY" ); // print extra output |
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153 | |
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154 | try { |
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155 | choose ( argc ) { |
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156 | case 4: |
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157 | if ( strcmp( argv[3], "d" ) != 0 ) { // default ? |
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158 | seed = convert( argv[3] ); if ( seed < 1 ) throw ExceptionInst( cmd_error ); // invalid ? |
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159 | } // if |
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160 | fallthrough; |
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161 | case 3: |
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162 | if ( strcmp( argv[2], "d" ) != 0 ) { // default ? |
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163 | numPlayers = convert( argv[2] ); if ( numPlayers < 2 ) throw ExceptionInst( cmd_error ); // invalid ? |
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164 | playersSet = true; |
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165 | } // if |
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166 | fallthrough; |
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167 | case 2: |
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168 | if ( strcmp( argv[1], "d" ) != 0 ) { // default ? |
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169 | numGames = convert( argv[1] ); if ( numGames < 0 ) throw ExceptionInst( cmd_error ); // invalid ? |
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170 | } // if |
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171 | fallthrough; |
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172 | case 1: ; // defaults |
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173 | default: // too many arguments |
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174 | throw ExceptionInst( cmd_error ); |
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175 | } // choose |
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176 | } catch( exception_t * ) { // catch any |
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177 | exit | "Usage: " | argv[0] |
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178 | | " [ games (>=0) | 'd' (default " | DefaultGames |
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179 | | ") [ players (>=2) | 'd' (random " | MinNoPlayers | "-" | MaxNoPlayers |
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180 | | ") [ seed (>0) | 'd' (random) ] ] ]"; |
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181 | } // try |
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182 | sout | numGames | numPlayers | seed; |
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183 | |
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184 | PRNG mprng, hprng, pprng; |
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185 | if ( seed != 0 ) { // specified on command line ? |
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186 | set_seed( mprng, seed ); set_seed( hprng, seed ); set_seed( pprng, seed ); |
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187 | } // if |
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188 | |
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189 | for ( game; 1 ~= numGames ) { |
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190 | if ( ! playersSet ) numPlayers = prng( mprng, MinNoPlayers, MaxNoPlayers ); |
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191 | sout | numPlayers | " players in the game"; |
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192 | { |
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193 | Potato potato{ hprng }; // hot potato to be tossed |
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194 | Player * players[numPlayers]; |
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195 | |
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196 | for ( unsigned int i = 0; i < (unsigned int)numPlayers; i += 1 ) { // start the players |
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197 | players[i] = malloc(); |
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198 | ?{}( *players[i], pprng, i, potato ); |
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199 | } // for |
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200 | |
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201 | // Do not swap player[0] with itself. |
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202 | unsigned int rposn = prng( mprng, 1, numPlayers - 1 ); // swap random position with 0 |
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203 | swap( players[0], players[rposn] ); |
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204 | |
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205 | // Tell each player its partner. |
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206 | for ( unsigned int i = 0; i < (unsigned int)numPlayers; i += 1 ) { |
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207 | init( *players[i], *players[leftOf(i, numPlayers)], *players[rightOf(i, numPlayers)] ); |
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208 | } // for |
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209 | |
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210 | &umpire = players[rposn]; // designate umpire and start game |
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211 | sout | "U " | nonl; |
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212 | toss( *players[rposn] ); |
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213 | delete( &umpire ); |
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214 | } |
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215 | if ( game < (unsigned int)numGames ) sout | nl | nl; // whitespace between games |
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216 | } // for |
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217 | } // main |
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218 | |
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219 | // Local Variables: // |
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220 | // compile-command: "make hotpotato" // |
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221 | // End: // |
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