Heres a way to do this with a doubly linked list with quicksort. This version of quicksort uses the last item in the
list as a pivot element when partitioning.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 | <br /> <br /> /****************************************************************<br /> * File Name : c:programstempCG.cpp<br /> * Date : January,6,2008<br /> * Comments : new project<br /> * Compiler/Assembler :<br /> * Modifications :<br /> *<br /> *<br /> *<br /> *<br /> *<br /> * Program Shell Generated At: 3:51:46 p.m.<br /> =-=-=-=-=-=-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=*/<br /> <br /> <br /> #include < iostream ><br /> #include < fstream ><br /> //#include < string.h ><br /> //#include < conio.h ><br /> //#include < math.h ><br /> #include < iomanip ><br /> #include < ctype.h ><br /> <br /> using namespace std;<br /> <br /> //>>>>>>>>>>>>>>>>>>>>>>>> GLOBAL DATA <<<<<<<<<<<<<<<<<<<<<<<<<<br /> <br /> const int MAX_NAME = 50;<br /> const int MAX_FILE_NAME = 50;<br /> const char STOP_SYMBOL = '*';<br /> enum keys { firstName , lastName , idNumber };<br /> keys sortKey ;<br /> #define OUTPUT_SPACES 15<br /> //<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<br /> <br /> <br /> <br /> struct person<br /> {<br /> <br /> char firstName [ MAX_NAME ] ;<br /> char lastName [ MAX_NAME ] ;<br /> char idNumber [ MAX_NAME ] ;<br /> person * prior;<br /> person * next;<br /> };<br /> <br /> <br /> //@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ FUNCTION PROTOTYPES @@@@@@@@@@@@@@@@@@@@@@@@@@<br /> <br /> bool readInputFile ( char * fileName , person *& frontList , person *& backList , int & itemsRead );<br /> void quickSort ( person ** front , person ** last , int numberItems );<br /> void swap ( person ** first , person ** last , person ** front , person ** back );<br /> void print ( person * list );<br /> void insertionSort ( person * list , int numberOfItems );<br /> void destroyList ( person * list );<br /> char * key ( person * node );<br /> <br /> //##################################################################################<br /> <br /> <br /> //main function ******************************<br /> <br /> int main ( )<br /> {<br /> <br /> person * front , * back;<br /> int items;<br /> <br /> sortKey = firstName;<br /> readInputFile ( "c:\programs\data.txt" , front , back , items );<br /> print ( front );<br /> quickSort ( & front , & back , items );<br /> cout << endl << endl;<br /> cout << "final ************************" << endl;<br /> print ( front );<br /> destroyList ( front );<br /> return 0 ;<br /> }<br /> <br /> <br /> /******************************* FUNCTION DEFINITION ******************************<br /> <br /> Name : readInputFile<br /> Parameters :<br /> <br /> fileName a(n) char * ,<br /> frontList a(n) person *& ( person *& ) ,<br /> backList a(n) person *& ( person *& ) ,<br /> itemsRead a(n) int &<br /> <br /> <br /> Returns: bool type<br /> Comments:<br /> <br /> <br /> <br /> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/<br /> bool readInputFile ( char * fileName , person *& frontList , person *& backList , int & itemsRead )<br /> {<br /> <br /> <br /> fstream inputFile;<br /> person * temp;<br /> char ch;<br /> inputFile.open ( fileName ); //open input file<br /> if ( inputFile.fail () )<br /> {<br /> cout << "input file did not open! " << endl;<br /> return false;<br /> }<br /> temp = new person; //make new node in list<br /> if ( temp == 0 ) //if allocation error<br /> {<br /> cout << "allocation error! " << endl;<br /> return false;<br /> }<br /> itemsRead = 1; //start count at 1<br /> frontList = backList = temp; //set front and back pointers to new node<br /> temp -> prior = 0; //set new nodes prior to empty<br /> inputFile >> temp -> firstName; //get nodes data from file<br /> inputFile >> temp -> lastName;<br /> inputFile >> temp -> idNumber;<br /> ch = inputFile.peek(); //check for end of file character<br /> while ( isspace ( ch ) ) //skip white space<br /> {<br /> inputFile.get();<br /> ch = inputFile.peek();<br /> }<br /> while ( ch != STOP_SYMBOL ) //while not at end of file<br /> {<br /> temp -> next = new person; //make new item in the list<br /> if ( temp -> next == 0 ) //check allocation<br /> {<br /> cout << "allocation error! " << endl;<br /> destroyList ( frontList );<br /> return false;<br /> }<br /> temp -> next -> prior = temp; //set temp to point to new node<br /> temp -> next -> next = 0; //set next to empty<br /> temp = temp -> next;//move list pointer to next node<br /> backList = temp; //make new node the back of list<br /> inputFile >> temp -> firstName; //get data<br /> inputFile >> temp -> lastName;<br /> inputFile >> temp -> idNumber;<br /> ch = inputFile.peek(); //get white space<br /> while ( isspace ( ch ) )<br /> {<br /> inputFile.get();<br /> ch = inputFile.peek();<br /> }<br /> itemsRead ++;//count items read<br /> }<br /> <br /> return true;<br /> }<br /> /******************************* FUNCTION DEFINITION ******************************<br /> <br /> Name : quickSort<br /> Parameters :<br /> <br /> front a(n) person *& ( person *& ) ,<br /> last a(n) person *& ( person *& ) ,<br /> numberItems a(n) int ( int )<br /> <br /> <br /> Returns: Void type<br /> Comments:<br /> <br /> <br /> <br /> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/<br /> void quickSort ( person ** low , person ** high , int numberItems )<br /> {<br /> <br /> <br /> person * savedLow = * low; //lowt<br /> person * savedHigh = * high;//hight<br /> person * tempLow , * tempHigh;<br /> person * pivot; //pivot for sorting<br /> <br /> if ( numberItems <= 1 ) //nothing to sort<br /> return;<br /> if ( numberItems == 2 ) //if 2 items then swap if needed<br /> {<br /> tempLow = * low;<br /> tempHigh = * high;<br /> if ( strcmp ( key ( tempLow ) , key ( tempHigh ) ) > 0 ) //swap items if out of order<br /> swap ( & tempLow , & tempHigh , & savedLow , & savedHigh );<br /> * low = tempLow; //reset low and high pointers<br /> * high = tempHigh;<br /> return ; //end function<br /> }<br /> <br /> <br /> <br /> pivot = savedHigh; //make the highest element in the array the pivot<br /> tempLow = savedLow; //start sorting at the lowest item in the list<br /> tempHigh = ( * savedHigh ).prior; //start sorting at the second to last item<br /> int lowCount = 1; //start counting at the first item for the low pointer<br /> int highCount = numberItems - 1; //start counting at the second to last item for high count<br /> <br /> do<br /> {<br /> <br /> //while items are less than the pivot move right<br /> while ( lowCount <= highCount && ( strcmp ( key ( tempLow ) , key ( pivot ) ) < 0 || strcmp ( key ( tempLow ) , key ( pivot ) ) == 0 ) )<br /> {<br /> <br /> <br /> tempLow = tempLow -> next;<br /> lowCount ++; //increase count of items behind pointer<br /> if ( ! tempLow )<br /> break;<br /> }<br /> //while items are greater than the pivot move right<br /> while ( lowCount <= highCount && ( strcmp ( key ( tempHigh ) , key ( pivot ) ) > 0 || strcmp ( key ( tempLow ) , key ( pivot ) ) == 0 ) )<br /> {<br /> <br /> <br /> tempHigh = tempHigh -> prior;<br /> highCount --; //decrease count of items before pointer<br /> if ( ! tempHigh )<br /> break;<br /> }<br /> <br /> if ( tempHigh ) //if top pointer has not crossed end of list , swap items<br /> swap ( & tempLow , & tempHigh , & savedLow , & savedHigh );<br /> <br /> } while ( lowCount <= highCount && tempHigh -> prior && tempLow -> next );<br /> <br /> if ( tempHigh ) //if high pointer has not passed the end to the list , exchange high and low pointers<br /> swap ( & tempLow , & tempHigh , & savedLow , & savedHigh );<br /> <br /> //put pivot in middle of large item and small item lists<br /> tempHigh = savedHigh;<br /> swap ( & tempLow , & tempHigh , & savedLow , & savedHigh );<br /> //sort list of small items<br /> quickSort ( & savedLow , & tempLow -> prior , lowCount - 1 );<br /> //sort list of large items<br /> quickSort ( & tempLow -> next , & savedHigh , numberItems - lowCount );<br /> //reset low and high pointers<br /> * low = savedLow;<br /> * high = savedHigh;<br /> <br /> return;<br /> }<br /> /******************************* FUNCTION DEFINITION ******************************<br /> <br /> Name : swap<br /> Parameters :<br /> <br /> first a(n) person *& ( person *& ) ,<br /> last a(n) person *& ( person *& )<br /> <br /> <br /> Returns: Void type<br /> Comments: first<br /> <br /> <br /> <br /> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/<br /> void swap ( person ** left , person ** right , person ** front , person ** back )<br /> {<br /> <br /> <br /> if ( ! * left || !* right ) //if left or right pointer is null , stop<br /> return;<br /> if ( * left == * right )<br /> return;<br /> //reset the front and back pointers<br /> if ( ( * front ) == ( * left ) ) //if left == front<br /> {<br /> <br /> * front = * right; //right is new front after swap<br /> }<br /> else if ( ( * front ) == ( * right ) ) //if right == front<br /> {<br /> <br /> * front = * left; //left is new front after swap<br /> }<br /> if ( ( * back ) == ( * left ) ) //if left == back<br /> {<br /> <br /> * back = * right; //right is back after swap<br /> }<br /> else if ( ( * back ) == ( * right ) ) //if right is back<br /> {<br /> <br /> * back = * left; //left is back after swap<br /> }<br /> <br /> <br /> <br /> person * tempN , * tempP;<br /> <br /> tempN = ( * left ) -> next; //save left's next and prior node setting<br /> tempP = ( * left ) -> prior;<br /> <br /> //case 1: right node follows left in list<br /> if ( ( * right ) -> prior == * left )<br /> {<br /> ( * left ) -> prior = ( * right ); //right is left's new prior node<br /> ( * left ) -> next = ( * right ) -> next; //left's next node is right's old prior node<br /> if ( ( * left ) -> next ) //if left had a next node<br /> ( * left ) -> next -> prior = ( * right ); //set that nodes prior to right<br /> ( * right ) -> next = ( * left ); //right's next now is left<br /> ( * right ) -> prior = tempP; //right's new prior is left's old prior<br /> if ( tempP ) //if left's old prior is not null<br /> tempP -> next = ( * right ); //left's old prior's next is right<br /> }<br /> //case 2: left follows right in the list<br /> else if ( ( * left) -> prior == ( * right ) )<br /> {<br /> ( * left ) -> prior = ( * right ) -> prior; //left's prior is now right's prior<br /> ( * left ) -> next = ( * right ); //left's next is now right<br /> if ( ( * right ) -> prior ) //if right's prior is not null<br /> ( * right ) -> prior -> next = ( * left ); //set its next to left<br /> ( * right ) -> prior = ( * left ); //right comes after left node now<br /> ( * right ) -> next = tempN; //right's next is left's old next<br /> if ( tempN ) //if left's old next is non-null<br /> tempN -> prior = ( * right ); //set its prior to right<br /> }<br /> //case 3: the two nodes are seperated by other nodes<br /> else<br /> {<br /> ( * left ) -> prior = ( * right ) -> prior; //left's prior equal's right's<br /> ( * left ) -> next = ( * right ) -> next; //left's next equal's right's<br /> <br /> if ( ( * right ) -> next ) //if right's next is non-null<br /> ( * right ) -> next -> prior = ( * left ); //set it's prior to left<br /> if ( ( * right ) -> prior )//if right's prior is non-null<br /> ( * right ) -> prior -> next = ( * left ); //it's next now equals left<br /> ( * right ) -> prior = tempP; //right's prior now == left's<br /> ( * right ) -> next = tempN; //right's next now == left's<br /> if ( tempP ) //if left's prior was non-null<br /> tempP -> next = ( * right ); //set its next to right<br /> if ( tempN ) //if left's next was non-null<br /> tempN -> prior = ( * right );//set its prior to right<br /> }<br /> <br /> <br /> person * temp = ( * left ); //swap left and right pointers to save<br /> person * temp2 = ( * right );//position of pointers in the list<br /> ( * left ) = temp2;<br /> ( * right ) = temp;<br /> <br /> return;<br /> }<br /> /******************************* FUNCTION DEFINITION ******************************<br /> <br /> Name : print<br /> Parameters :<br /> <br /> list a(n) person * ( person * )<br /> <br /> <br /> Returns: Void type<br /> Comments:<br /> <br /> <br /> <br /> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/<br /> void print ( person * list )<br /> {<br /> <br /> cout << endl;<br /> <br /> cout << setiosflags ( ios::left );<br /> cout << setw ( OUTPUT_SPACES ) << "first name"<br /> << setw ( OUTPUT_SPACES ) << "last name"<br /> << setw ( OUTPUT_SPACES ) << "id number" << endl << endl;<br /> while ( list ) //while not at the end of the list<br /> {<br /> //output name ect....<br /> cout << setw ( OUTPUT_SPACES ) << list -> firstName << " " << setw ( OUTPUT_SPACES ) << list -> lastName << " " << setw ( OUTPUT_SPACES ) << list -> idNumber << endl;<br /> list = list -> next;<br /> <br /> }<br /> <br /> return;<br /> }<br /> <br /> /******************************* FUNCTION DEFINITION ******************************<br /> <br /> Name : destroyList<br /> Parameters :<br /> <br /> list a(n) person * ( person * )<br /> <br /> <br /> Returns: Void type<br /> Comments:<br /> <br /> <br /> <br /> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/<br /> void destroyList ( person * list )<br /> {<br /> <br /> person * temp;<br /> <br /> while ( list ) //for each item in the list , destroy the list<br /> {<br /> temp = list;<br /> list = list -> next;<br /> delete temp;<br /> }<br /> <br /> <br /> return;<br /> }<br /> /******************************* FUNCTION DEFINITION ******************************<br /> <br /> Name : key<br /> Parameters :<br /> <br /> first a(n) person * ( person * ) ,<br /> second a(n) person * ( person * )<br /> <br /> <br /> Returns: char type<br /> Comments: use a macro for this......<br /> <br /> <br /> <br /> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/<br /> char * key ( person * node )<br /> {<br /> <br /> switch ( sortKey )<br /> {<br /> case firstName:<br /> return node -> firstName;<br /> case lastName:<br /> return node -> lastName;<br /> case idNumber:<br /> return node -> idNumber;<br /> <br /> };<br /> <br /> <br /> }<br /> |
input:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | <br /> bob johns 222<br /> suzie barker 333<br /> adam west 555<br /> zack wilde 111<br /> janet woods 444<br /> qubert johns 666<br /> barak obama 777<br /> carly simon 888<br /> curt cobain 999<br /> tom gadja 1010<br /> larry bear 1111<br /> pilar nuffer 1212<br /> mikey scalcee 1313<br /> old puff 1414<br /> charolette phifer 1515<br /> don dokken 46464<br /> adam ant 555<br /> willodean mcqueen 222<br /> *<br /> |
output ( sorting with first name as key ):
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | <br /> first name last name id number<br /> <br /> adam ant 555<br /> adam west 555<br /> barak obama 777<br /> bob johns 222<br /> carly simon 888<br /> charolette phifer 1515<br /> curt cobain 999<br /> don dokken 46464<br /> janet woods 444<br /> larry bear 1111<br /> mikey scalcee 1313<br /> old puff 1414<br /> pilar nuffer 1212<br /> qubert johns 666<br /> suzie barker 333<br /> tom gadja 1010<br /> willodean mcqueen 222<br /> zack wilde 111<br /> Press any key to continue<br /> |