利用键盘模拟进程的三种操作状态，并且使用C++中的list模板模拟内存的分配和回收。
能够模拟进程的创建与撤销过程
l可对进程的状态进行全面的控制
按先进先出方式管理就绪和阻塞队列，能够按队列形式输出进程状
用PCB代表进程，用全局变量表示进程的个数。
1 #include <iostream> 2 #include <list> 3 #include <numeric> 4 #include <algorithm> 5 #include<stdlib.h> 6 using namespace std; 7 8 9 struct PCB //PCB结构体 10 { 11 char name[10]; //外部标记 12 int PID; //内部标记 13 int begin; //起始地址 14 int length; //长度 15 struct PCB* next; 16 }; 17 18 19 struct Memory 20 { 21 int start; //起始地址 22 int len; //长度 23 bool operator < (const struct Memory p) const 24 { 25 return len < p.len; 26 } 27 28 }; 29 typedef list <Memory> Memy;//用模板定义Memory的列表 30 31 int SIZE; //用来存储内存的大小 32 Memy LM; //用来存储内存分配的链表 33 Memy::iterator K; 34 Memory L; //第一块完整的内存 35 static int number = 0; 36 //number用来标记进程的数量。 37 38 //创建三个链表，分别代表，就绪，执行，阻塞 39 struct PCB* Ready = new struct PCB; 40 struct PCB* Blocked = new struct PCB; 41 struct PCB* Running = new struct PCB; 42 43 44 bool px(struct Memory m, struct Memory n) 45 { 46 return m.start < n.start; 47 } 48 49 50 void CreateProcess(struct PCB* &Ready, Memy &LM)//创建进程 51 { 52 LM.sort(); 53 struct PCB* P = new struct PCB; 54 struct PCB* X = new struct PCB;//利用X来做到插入队尾 55 56 X = Ready; 57 58 //cout << "请输入此进程的名称：" << endl; 59 cin >> P->name; 60 61 62 //cout << "请输入此进程大小：" << endl; 63 cin >> P->length; 64 65 for (K = LM.begin(); K != LM.end(); K++)//分配内存， 66 { 67 Memy::iterator x; 68 if (K->len <= 0) 69 { 70 cout << "已经没有足够的内存空间！" << endl; 71 return; 72 } 73 if (K->len < P->length) 74 { 75 x = K; 76 K++; 77 if (K == LM.end()) 78 { 79 cout << "已经没有足够的内存空间！" << endl; 80 return; 81 } 82 else 83 { 84 K = x; 85 continue; 86 } 87 } 88 else if (K->len >= P->length) 89 { 90 if (K->len - P->length <= 2) 91 { 92 P->begin = K->start; 93 P->length = K->len; 94 LM.erase(K); 95 number++; 96 break; 97 } 98 else 99 { 100 P->begin = K->start; 101 K->start += P->length;//修改起始地址 102 K->len -= P->length; 103 number++; 104 break; 105 } 106 } 107 else 108 { 109 continue; 110 } 111 } 112 113 P->PID = number; //利用number来进行唯一系统内部进程标示 114 while (X->next != NULL) //新建节点连接到链表尾部 115 { 116 X = X->next; 117 } 118 X->next = P; 119 P->next = NULL; 120 } 121 122 123 void sort1(Memy &LM) //按照长度进行排序 124 { 125 LM.sort(); 126 } 127 128 129 void EndProcess(struct PCB* &Running, Memy &LM) //结束进程 130 { 131 if (Running->next == NULL) 132 { 133 cout << "没有进程处于执行态！" << endl; 134 system("pause"); 135 return; 136 } 137 LM.sort(px); 138 Memory O; 139 O.start = Running->next->begin; 140 O.len = Running->next->length; 141 if (LM.size() == 0) //系统剩余空间为0，直接插入。 142 { 143 Memory M; 144 M.len = O.len; 145 M.start = O.start; 146 LM.push_back(M); 147 } 148 else 149 { 150 for (K = LM.begin(); K != LM.end(); K++) 151 { 152 if (K->start>(O.start + O.len)) //上下都被占用 直接插入前面 153 { 154 Memory m; 155 m.len = O.len; 156 m.start = O.start; 157 LM.push_front(m); 158 break; 159 } 160 else if ((O.start + O.len) == K->start) //上占下空 改下区基址，改长度 161 { 162 K->start = O.start; 163 K->len += O.len; 164 break; 165 } 166 else if ((K->start + K->len) == O.start) //上空============================================== 167 { 168 int l = K->len; 169 Memy::iterator X; 170 X = K; 171 ++K; 172 if (K != LM.end()) 173 { 174 if (K->start == (O.start + O.len)) //上空下空 175 { 176 X->len = K->len + l + O.len; //长度三合一//删除++K 177 LM.erase(K); 178 break; 179 } 180 else //上空 下占 改上区长度 181 { 182 X->len += O.len; 183 break; 184 } 185 } 186 else //上空 下占 改上区长度 187 { 188 X->len += O.len; 189 break; 190 } 191 } 192 else if ((K->start + K->len)<O.start) //提前进入下一次循环 193 { 194 continue; 195 } 196 } 197 } 198 199 200 while (Running->next != NULL) 201 { 202 struct PCB* P = Running->next; 203 P->next = NULL; 204 delete P; 205 Running->next = NULL; 206 number--; 207 } 208 } 209 210 211 void show(struct PCB* Ready, struct PCB* Running, struct PCB* Blocked)//显示三种状态的进程情况 212 { 213 cout << "就绪态："; 214 while (Ready->next != NULL) 215 { 216 cout << " name: " << Ready->next->name << " begin: " << Ready->next->begin << " length: " << Ready->next->length; 217 Ready = Ready->next; 218 } 219 cout << endl; 220 cout << "执行态："; 221 if (Running->next != NULL) 222 { 223 cout << "name: " << Running->next->name << " begin: " << Running->next->begin << " len: " << Running->next->length; 224 } 225 cout << endl; 226 cout << "阻塞态:"; 227 while (Blocked->next != NULL) 228 { 229 cout << "name: " << Blocked->next->name << " begin: " << Blocked->next->begin << " len: " << Blocked->next->length; 230 Blocked = Blocked->next; 231 } 232 cout << endl; 233 int sum = 0; 234 for (K = LM.begin(); K != LM.end(); K++) 235 { 236 cout << "内存起始地址： " << K->start << "内存长度：" << K->len << endl; 237 sum += K->len; 238 } 239 cout << "进程所占空间: " << (SIZE - sum) << endl; 240 cout << "系统空闲空间: " << sum << endl; 241 sum = 0; 242 } 243 244 245 void Run(struct PCB* &Ready, struct PCB* &Running) //执行函数，查询就绪态中的PCB 246 { 247 while ((Ready->next != NULL) && (Running->next == NULL)) 248 { 249 struct PCB* Z = Ready->next; 250 Running->next = Z; 251 Ready->next = Ready->next->next; 252 Z->next = NULL; 253 } 254 } 255 256 257 void Block(struct PCB* &Running, struct PCB* &Blocked) //执行到阻塞的转换 258 { 259 struct PCB* Head = Blocked; 260 while (Running->next != NULL) 261 { 262 while (Head->next != NULL) 263 { 264 Head = Head->next; 265 } 266 Head->next = Running->next; 267 Running->next = NULL; 268 } 269 } 270 271 272 void TimeUp(struct PCB* &Running, struct PCB* &Ready) //时间片到 273 { 274 struct PCB* Head = Ready; 275 struct PCB* P = Running->next; 276 P->next = NULL; 277 while (Running->next != NULL) 278 { 279 while (Head->next != NULL) 280 { 281 Head = Head->next; 282 } 283 Head->next = P; 284 Running->next = NULL; 285 } 286 } 287 288 289 void Wake(struct PCB* &Blocked, struct PCB* &Ready)//唤醒进程 290 { 291 if (Blocked->next == NULL) 292 { 293 cout << "没有进程处于阻塞态！" << endl; 294 system("pause"); 295 return; 296 } 297 struct PCB* P = Ready; 298 while (P->next != NULL) 299 { 300 P = P->next; 301 } 302 if (Blocked->next != NULL) 303 { 304 P->next = Blocked->next; 305 Blocked->next = Blocked->next->next; 306 P->next->next = NULL; 307 } 308 else 309 { 310 cout << "没有处于阻塞状态的进程！" << endl; 311 } 312 313 } 314 315 316 void interface() 317 { 318 cout << "========帮助========" << endl; 319 cout << "C----------创建进程" << endl; 320 cout << "T----------时间片到" << endl; 321 cout << "S----------进程阻塞" << endl; 322 cout << "W----------唤醒进程" << endl; 323 cout << "E----------结束进程" << endl; 324 cout << "H----------查看帮助" << endl; 325 326 } 327 328 329 void start() 330 { 331 cout << "请输入内存的起始地址：" << endl; 332 cin >> L.start; 333 cout << "请输入内存的大小：" << endl; 334 cin >> L.len; 335 SIZE = L.len; 336 LM.push_front(L); 337 } 338 339 340 void process() // 中间过程 341 { 342 interface(); 343 system("pause"); 344 char choice; 345 do 346 { 347 system("cls"); 348 cin >> choice; 349 switch (choice) 350 { 351 case 'C':LM.sort(px); CreateProcess(Ready, LM); Run(Ready, Running); show(Ready, Running, Blocked); system("pause"); break; 352 case 'T':TimeUp(Running, Ready); Run(Ready, Running); show(Ready, Running, Blocked); system("pause"); break; 353 case 'S':Block(Running, Blocked); Run(Ready, Running); show(Ready, Running, Blocked); system("pause"); break; 354 case 'W':Wake(Blocked, Ready); Run(Ready, Running); show(Ready, Running, Blocked); system("pause"); break; 355 case 'E':EndProcess(Running, LM); Run(Ready, Running); show(Ready, Running, Blocked); sort1(LM); system("pause"); break; 356 case 'H':interface();break; 357 default:cout << "输入错误，请重新输入！" << endl; system("pause"); break; 358 } 359 360 } while (number != 0); 361 } 362 363 364 void main() 365 { 366 Ready->next = NULL; 367 Blocked->next = NULL; 368 Running->next = NULL; 369 start(); 370 process(); 371 cout << "所有进程已结束" << endl; 372 system("pause"); 373 374 }
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