操作系统存储器管理——最佳适应算法

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1、存储管理上机作业——最佳适应算法以最佳适应为例，给出可变式分区的分配回收算法。源程序如下：#include#defineN5structfreearea{intstartaddress;intsize;intstate;}freeblock[N]={{20,20,1},{80,30,1},{160,10,1},{200,40,0},{250,50,1}};intallocate(intapplyarea){inti,tag=0;for(i=0;iapplyarea&&freeblock[i].s

2、tate==1){freeblock[i].startaddress=freeblock[i].startaddress+applyarea;freeblock[i].size=freeblock[i].size-applyarea;tag=1;//有满足条件的分区时，tag置1returnfreeblock[i].startaddress-applyarea;}elseif(freeblock[i].size==applyarea&&freeblock[i].state==1){freeblock[i].state=0;tag=1;//有满足条件的分区时，tag置1r

3、eturnfreeblock[i].startaddress;}}if(tag==0)return-1;}voidset_free(){inti,j,s,l,tag1=0,tag2=0,tag3=0;printf("pleaseinputthestartaddressyouwanttosetfree:");scanf("%d",&s);printf("pleaseinputthesize:");scanf("%d",&l);for(i=0;i

4、eeblock[i].state==1)//释放区与某一空闲块的高地址相邻接{l=freeblock[i].size+l;tag1=1;//释放区与某一空闲块的高地址相邻接for(j=0;j

5、startaddress;freeblock[i].state=0;tag2=1;//标记同时与两个空闲块相接break;}}if(tag2==0){freeblock[i].startaddress=s;freeblock[i].size=l;break;}}}//forif(tag1==0)//不与空闲块的高地址相接{for(i=0;i

6、ock[i].size=freeblock[i].size+l;tag3=1;break;}if(tag3==0)//不与任何空闲块相接{for(j=0;jf

7、reeblock[j].size){temp.size=freeblock[i].size;temp.startaddress=freeblock[i].startaddress;temp.state=freeblock[i].state;freeblock[i].size=freeblock[j].size;freeblock[i].startaddress=freeblock[j].startaddress;freeblock[i].state=freeblock[j].state;freeblock[j].size=temp.siz