實驗三進程調度1．目的和要求進程調度是處理機管理的核心內容。本實驗要求用C語言編寫和調試一個簡單的進程調度程序。通過本實驗可以加深理解有關進程控制塊、進程隊列的概念，并體會和了解優(yōu)先數(shù)和時間片輪轉調度算法的具體實施方法。2．實驗內容①設計進程控制塊PCB表結構，分別適用于優(yōu)先數(shù)調度算法和循環(huán)輪轉調度算法。②建立進程就緒隊列。對兩種不同算法編制入鏈子程序。③編制兩種進程調度算法：1〕優(yōu)先數(shù)調度；2〕循環(huán)輪轉調度3．實驗環(huán)境①PC兼容機②Windows、DOS系統(tǒng)、Turboc2.0③C語言4．實驗提示①本程序用兩種算法對五個進程進行調度，每個進程可有三個狀態(tài)，并假設初始狀態(tài)為就緒狀態(tài)。②為了便于處理，程序中的某進程運行時間以時間片為單位計算。各進程的優(yōu)先數(shù)或輪轉時間數(shù)以及進程需運行的時間片數(shù)的初始值均由用戶給定。③在優(yōu)先數(shù)算法中，優(yōu)先數(shù)可以先取值為50-進程執(zhí)行時間，進程每執(zhí)行一次，優(yōu)先數(shù)減3，CPU時間片數(shù)加1，進程還需要的時間片數(shù)減1。在輪轉算法中，采用固定時間片〔即：每執(zhí)行一次進程，該進程的執(zhí)行時間片數(shù)為已執(zhí)行了2個單位〕，這時，CPU時間片數(shù)加2，進程還需要的時間片數(shù)減2，并排列到就緒隊列的尾上。④對于遇到優(yōu)先數(shù)一致的情況，采用FIFO策略解決。5．實驗程序#include<stdio.h>#include<dos.h>#include<stdlib.h>#include<conio.h>#include<io.h>#defineP_NUM3#defineP_TIME50enumstate{ ready, execute, block, finish};structpcb{ charname[4]; intpriority; intcputime; intneedtime; intcount; intround; enumstateprocess; structpcb*next;};structpcb*get_process();structpcb*get_process(){ structpcb*q; structpcb*t; structpcb*p; inti=0; printf("inputnameandneedtime,pleaseinput3processes\n"); while(i<P_NUM){ q=(structpcb*)malloc(sizeof(structpcb)); scanf("%s",&(q->name)); scanf("%d",&(q->needtime)); q->cputime=0; q->priority=P_TIME-q->needtime; q->process=ready; q->next=NULL; if(i==0){ p=q; t=q; } else{ t->next=q; t=q; } i++; }/*while*/ returnp;}voiddisplay(structpcb*p){ printf("namecputimeneedtimeprioritystate\n"); while(p){ printf("%s",p->name); printf(""); printf("%d",p->cputime); printf(""); printf("%d",p->needtime); printf(""); printf("%d",p->priority); printf(""); switch(p->process){ caseready: printf("ready\n"); break; caseexecute: printf("execute\n"); break; caseblock: printf("block\n"); break; casefinish: printf("finish\n"); break; } p=p->next; }}intprocess_finish(structpcb*q){ intbl=1; while(bl&&q){ bl=bl&&q->needtime==0; q=q->next; } returnbl;}voidcpuexe(structpcb*q){ structpcb*t=q; intmax_priority=0; while(q){ if(q->process!=finish){ q->process=ready; if(q->needtime==0){ q->process=finish; } } if(max_priority<q->priority&&q->process!=finish){ max_priority=q->priority; t=q; } q=q->next; } if(t->needtime!=0){ t->priority-=3; t->needtime--; t->process=execute; t->cputime++; }}voidpriority_cal(){ structpcb*p; intcpu=0; p=get_process(); while(!process_finish(p)){ cpu++; printf("cputime:%d\n",cpu); cpuexe(p); display(p); sleep(5); } printf("Allprocesseshavefinished,pressanykeytoexit"); getch();}voiddisplay_menu(){ printf("CHOOSETHEALGORITHM:\n"); printf("1PRIORITY\n"); printf("2ROUNDROBIN\n"); printf("3EXIT\n");}structpcb*get_process_round(){ structpcb*q; structpcb*t; structpcb*p; inti=0; printf("inputnameandtime,pleaseinput3processes\n"); while(i<P_NUM){ q=(structpcb*)malloc(sizeof(structpcb)); scanf("%s",&(q->name)); scanf("%d",&(q->needtime)); q->cputime=0; q->round=0; q->count=0; q->process=ready; q->next=NULL; if(i==0){ p=q; t=q; } else{ t->next=q; t=q; } i++; }/*while*/ returnp;}voidcpu_round(structpcb*q){ q->cputime+=2; q->needtime-=2; if(q->needtime<0){ q->needtime=0; } q->count++; q->round++; q->process=execute;}structpcb*get_next(structpcb*k,structpcb*head){ structpcb*t; t=k; do{ t=t->next; } while(t&&t->process==finish); if(t==NULL){ t=head; while(t->next!=k&&t->process==finish){ t=t->next; } } returnt;}voidset_state(structpcb*p){ while(p){ if(p->needtime==0){ p->process=finish; } if(p->process==execute){ p->process=ready; } p=p->next; }}voiddisplay_round(structpcb*p){ printf("NAMECPUTIMENEEDTIMECOUNTROUNDSTATE\n"); while(p){ printf("%s",p->name); printf(""); printf("%d",p->cputime); printf(""); printf("%d",p->needtime); printf(""); printf("%d",p->count); printf(""); printf("%d",p->round); printf(""); switch(p->process){ caseready: printf("ready\n"); break; caseexecute: printf("execute\n"); break; casefinish: printf("finish\n"); break; } p=p->next; }}voidround_cal(){ structpcb*p; structpcb*r; intcpu=0; p=get_process_round(); r=p; while(!process_finish(p)){ cpu+=2; cpu_round(r); r=get_next(r,p); printf("cpu%d\n",cpu); display_round(p); set_state(p); sleep(5); }printf("Allprocesseshavefinished,pressanykeytoexit"); getch();}/*主程序*/voidmain(){ intuser_input; display_menu(); scanf("%d",&user_input); switch(user_input){ case1:priority_cal();break; case2:round_cal();break;