模拟进程调度算法

模拟短作业优先算法、时间片轮转法和优先数算法的执行情况，并动态画出其进程执行的Gantt图，计算以上算法的每个进程的响应时间和周转时间。

/*name：getingtime：2014-12-10*/#include<iostream>using namespace std;const int MAX = 100;//定义进程结构体struct process{char p_name[10];//进程名int reach_time;//到达时间int run_time;//剩余运行时间int priority;//优先级int response_time;//响应时间int turnaround_time;//周转时间};struct gantt{char p_name[10];//进程名int run_time;//运行时间};process p[MAX];//进程数组gantt g[MAX];//Gantt图数组int p_Num;//实际进程数char FileName[20];//进程序列文件名int MaxReachTime;//最大到达时间int BeReached[MAX];//到达进程数组int reach_Num;//到达进程数//读文件int ReadFile(){FILE *fp; int i; char c;cout << "请输入要打开的文本文件名(注意：包括路径名和后缀名)： "; cin >> FileName; if((fp = fopen(FileName,"r")) == NULL){ cout << "错误：文件 " << FileName << " 打不开,请检查文件名和路径!!" << endl; exit(0);} else{c = fgetc(fp);while(c == ' ' || c == 10 || c == 9)//过滤空格、换行和TAB字符{c = fgetc(fp);}if(c == EOF){printf("错误：文件：%s 为空!!\n", FileName);exit(0);}else{fseek(fp, -1, SEEK_CUR); while(!feof(fp)){ fscanf(fp, "%s %d %d %d", p[p_Num].p_name, &p[p_Num].reach_time, &p[p_Num].run_time, &p[p_Num].priority); p_Num++; }//输出所读入的进程数据cout << endl << "从文件 " << FileName << " 读入的进程数据：" << endl << endl; cout << "进程名  到达时间  运行时间  优先数" << endl; for(i = 0; i < p_Num; i++){ cout << "  " << p[i].p_name << "       " << p[i].reach_time << "      " << p[i].run_time << "      " << p[i].priority << endl; } cout << endl << "进程总数：" << p_Num << endl << endl; return 0;}}}//找到所有进程中的最大到达时间void GetMaxReachTime(){for(int i = 0; i < p_Num; i++){if(p[i].reach_time > MaxReachTime) MaxReachTime = p[i].reach_time;}}//全部初始化void Init(){for(int i = 0; i < MAX; i++){strcpy(p[i].p_name, "");p[i].reach_time = -1;p[i].run_time = -1;p[i].priority = -1;p[i].response_time = -1;p[i].turnaround_time = -1;strcpy(g[i].p_name, "");g[i].run_time = 0;BeReached[i] = -1;}p_Num = 0;MaxReachTime = 0;reach_Num = 0;ReadFile();GetMaxReachTime();}//检查是否所有进程都运行结束bool CheckFinish(){for(int i = 0; i < p_Num; i++){if(p[i].run_time > 0) return false;}return true;}//显示Gantt图void ShowGantt(){int i = 0;cout << "Gantt图如下所示：" << endl << endl;cout << "进程名运行时间" << endl;while(true){if(g[i].run_time == 0) break;cout << "  " << g[i].p_name << "   " << g[i].run_time << endl;i++;}cout << endl;}//显示每个进程的响应时间和周转时间void ShowTime(){int i = 0;cout << "进程名 响应时间 周转时间" << endl;while(i < p_Num){cout << "  " << p[i].p_name << "  " << p[i].response_time << "   " << p[i].turnaround_time << endl;i++;}cout << endl;}//更新到达进程数组和到达进程数void UpdateReachArray(int t){if(t <= MaxReachTime){for(int i = 0; i < p_Num; i++){if(p[i].reach_time - t == 0){BeReached[reach_Num++] = i;}}}}//短作业优先算法，抢占调度void SPN(){int t = 0, i, j = -1;int ilMin;//上次最短进程下标int iMin = -1;//当前最短进程下标int iMinRuntime;//当前最短运行时间while(true){UpdateReachArray(t);//更新到达进程数组ilMin = iMin;iMinRuntime = 100000;for(i=0; i<reach_Num; i++)//找到剩余运行时间最短的进程{ if(p[BeReached[i]].run_time > 0 && p[BeReached[i]].run_time < iMinRuntime){ iMin = BeReached[i]; iMinRuntime = p[BeReached[i]].run_time; } }if(ilMin != iMin)//若当前运行进程和上个运行进程不是同一个，则j++{j++;strcpy(g[j].p_name, p[iMin].p_name);}g[j].run_time += 1;p[iMin].run_time -= 1;if(p[iMin].response_time == -1) p[iMin].response_time = t - p[iMin].reach_time;//记录该进程响应时间if(p[iMin].run_time == 0) p[iMin].turnaround_time = t + 1 - p[iMin].reach_time;//记录该进程周转时间if(CheckFinish()) break;t++;//时间加1}ShowGantt();ShowTime();}//时间片轮转法算法，抢占调度，BTime为时间片大小的参数void RR(int BTime){int t = 0, j = 0, k = 0;int FBTime = 0;//已用时间片长度while(true){UpdateReachArray(t);if(FBTime == BTime || p[BeReached[k]].run_time == 0) //时间片用完或当前运行进程已结束{j++;k++;FBTime = 0;//已用时间片清零}if(k == reach_Num) k = 0;//已运行到队列最后进程之后，从队列最前重新运行while(p[BeReached[k]].run_time == 0)//如果该进程已运行结束，跳到下一个进程{k++;if(k == reach_Num) k = 0;}strcpy(g[j].p_name, p[BeReached[k]].p_name);g[j].run_time += 1;p[BeReached[k]].run_time -= 1;if(p[BeReached[k]].response_time == -1) p[BeReached[k]].response_time = t - p[BeReached[k]].reach_time;//记录该进程响应时间if(p[BeReached[k]].run_time == 0) p[BeReached[k]].turnaround_time = t + 1 - p[BeReached[k]].reach_time;//记录该进程周转时间if(CheckFinish()) break;t++;//时间加1FBTime++;//已用时间片加1}ShowGantt();ShowTime();}//优先数算法void Priority(){int t = 0, i, j = -1;int ilMin;//上次最高优先级进程下标int iMin = -1;//当前最高优先级进程下标int iMinPriority;//当前最高优先级（数值小的优先级高）while(true){UpdateReachArray(t);//更新到达进程数组ilMin = iMin;iMinPriority = 100;for(i = 0; i < reach_Num; i++)//找到优先级最高的进程{ if(p[BeReached[i]].run_time > 0 && p[BeReached[i]].priority < iMinPriority){ iMin = BeReached[i]; iMinPriority = p[BeReached[i]].priority; } }if(ilMin != iMin)//若当前运行进程和上个运行进程不是同一个，则j++{j++;strcpy(g[j].p_name, p[iMin].p_name);}g[j].run_time += 1;p[iMin].run_time -= 1;if(p[iMin].response_time == -1) p[iMin].response_time = t - p[iMin].reach_time;//记录该进程响应时间if(p[iMin].run_time == 0) p[iMin].turnaround_time = t + 1 - p[iMin].reach_time;//记录该进程周转时间if(CheckFinish()) break;t++;//时间加1}ShowGantt();ShowTime();}void Information(){cout << "***********************************提示信息***********************************" << endl;cout << "文本文件格式为：" << endl;cout << "进程名 到达时间 运行时间 优先级" << endl << endl;}void main(){Information();cout << "********************************短作业优先算法********************************" << endl << endl;Init();SPN();cout << "****************************时间片轮转法(时间片为1)***************************" << endl << endl;Init();RR(1);cout << "****************************时间片轮转法(时间片为2)***************************" << endl << endl;Init();RR(2);cout << "****************************时间片轮转法(时间片为3)***************************" << endl << endl;Init();RR(3);cout << "**********************************优先数算法**********************************" << endl << endl;Init();Priority();}