计算机操作系统动态分区.docx
《计算机操作系统动态分区.docx》由会员分享，可在线阅读，更多相关《计算机操作系统动态分区.docx（15页珍藏版）》请在冰豆网上搜索。
计算机操作系统动态分区
动态分区算法
源代码：
#include"stdio.h"
#defineN5
intstart;
structfreearea
{
intstartaddress;
intsize;
intstate;
}freeblock[N]={{20,20,1},{80,50,1},{150,30,1},{300,30,0},{600,10,1}};
intalloc（intapplyarea）
{
inti,tag=0;
for（i=0;iif（freeblock[i].state==1&&freeblock[i].size>applyarea）
{
freeblock[i].startaddress=freeblock[i].startaddress+applyarea;
freeblock[i].size=freeblock[i].size-applyarea;
tag=1;
returnfreeblock[i].startaddress-applyarea;
}
else
if（freeblock[i].state==1&&freeblock[i].size==applyarea）
{
freeblock[i].state=0;
tag=1;
returnfreeblock[i].startaddress;
}
if（tag==0）
return-1;
}
intalloc2（intapplyarea,ints）
{
inti,tag=0;
for（i=s;iif（freeblock[i].state==1&&freeblock[i].size>applyarea）
{
freeblock[i].startaddress=freeblock[i].startaddress+applyarea;
freeblock[i].size=freeblock[i].size-applyarea;
tag=1;
start=freeblock[i].startaddress-applyarea;
returni;
}
else
if（freeblock[i].state==1&&freeblock[i].size==applyarea）
{
freeblock[i].state=0;
tag=1;
start=freeblock[i].startaddress;
returni;
}
if（tag==0）
return-1;
}
intalloc3（intapplyarea）
{
inti,k,h,flag,tag=0,j=0;
inta[N];
structfreeareamin;
structfreeareamid;
for（i=0;i{
if（freeblock[i].state==1&&freeblock[i].size==applyarea）
{
freeblock[i].state=0;
tag=1;
returnfreeblock[i].startaddress;
}
}
for（i=0;i{
if（freeblock[i].state==1&&freeblock[i].size>applyarea）a[j++]=i;
}
if（j>1）
{
h=a[0];
min=freeblock[h];
for（k=1;k{
h=a[k];
if（freeblock[h].size{
mid.size=freeblock[h].size;
mid.state=freeblock[h].state;
mid.startaddress=freeblock[h].startaddress;
freeblock[h].size=min.size;
freeblock[h].state=min.state;
freeblock[h].startaddress=min.startaddress;
min.size=mid.size;
min.state=mid.state;
min.startaddress=mid.startaddress;
}
}
min.startaddress=min.startaddress+applyarea;
min.size=min.size-applyarea;
tag=1;
returnmin.startaddress-applyarea;
}
elseif（j==1）
{
h=a[0];
min=freeblock[h];
min.startaddress=min.startaddress+applyarea;
min.size=min.size-applyarea;
tag=1;
returnmin.startaddress-applyarea;
}
if（tag==0）
return-1;
}
voidsetfree（）
{
ints,l,tag1=0,tag2=0,tag3=0,i,j;
printf（"inputfreeareastartaddress:
\n"）;
scanf（"%d",&s）;
printf（"inputfreeareasize:
\n"）;
scanf（"%d",&l）;
for（i=0;i{
if（freeblock[i].startaddress==s+l&&freeblock[i].state==1）
{
l=l+freeblock[i].size;
tag1=1;
for（j=0;jif（freeblock[j].startaddress+freeblock[j].size==s&&freeblock[j].state==1）
{
freeblock[i].state=0;
freeblock[j].size=freeblock[j].size+l;
tag2=1;
break;
}
if（tag2==0）
{
freeblock[i].startaddress=s;
freeblock[i].size=l;
break;
}
}
}
if（tag1==0）
{
for（i=0;iif（freeblock[i].startaddress+freeblock[i].size==s&&freeblock[i].state==1）
{
freeblock[i].size=freeblock[i].size+l;
tag3=1;
break;
}
if（tag3==0）
for（j=0;jif（freeblock[j].state==0）
{
freeblock[j].startaddress=s;
freeblock[j].size=l;
freeblock[j].state=1;
break;
}
}
}
voidadjust（）
{
inti,j;
structfreeareamiddata;
for（i=0;ifor（j=0;jif（freeblock[j].startaddress>freeblock[j+1].startaddress）
{
middata.startaddress=freeblock[j].startaddress;
middata.size=freeblock[j].size;
middata.state=freeblock[j].state;
freeblock[j].startaddress=freeblock[j+1].startaddress;
freeblock[j].size=freeblock[j+1].size;
freeblock[j].state=freeblock[j+1].state;
freeblock[j+1].startaddress=middata.startaddress;
freeblock[j+1].size=middata.size;
freeblock[j+1].state=middata.state;
}
for（i=0;ifor（j=0;jif（freeblock[j].state==0&&freeblock[j+1].state==1）
{
middata.startaddress=freeblock[j].startaddress;
middata.size=freeblock[j].size;
middata.state=freeblock[j].state;
freeblock[j].startaddress=freeblock[j+1].startaddress;
freeblock[j].size=freeblock[j+1].size;
freeblock[j].state=freeblock[j+1].state;
freeblock[j+1].startaddress=middata.startaddress;
freeblock[j+1].size=middata.size;
freeblock[j+1].state=middata.state;
}
}
voidprint（）
{
inti;
printf（"|---------------------------------------------------------------|\n"）;
printf（"|startsizestate|\n"）;
printf（"|---------------------------------------------------------------|\n"）;
for（i=0;i{
printf（"|%3d%3d%3d|\n",
freeblock[i].startaddress,freeblock[i].size,freeblock[i].state）;
printf（"|---------------------------------------------------------------|\n"）;
}
}
voidshouci（）
{
intapplyarea,start,i,j;
charend;
getchar（）;
printf（"\nisthereanyjobrequestmemory?
yorn:
"）;
while（（end=getchar（））=='y'）
{
printf（"atfirstthefreememoryisthis:
\n"）;
adjust（）;
print（）;
printf（"inputrequestmemorysize:
"）;
scanf（"%d",&applyarea）;
start=alloc（applyarea）;
if（start==-1）
printf（"thereisnofitmemory,pleasewait\n"）;
else
{
adjust（）;
printf（"afterallocation,thefreememoryisthis:
\n"）;
print（）;
printf（"job'smemorystartaddressis:
%d\n",start）;
printf（"jobsizeis:
%d\n",applyarea）;
printf（"jobisrunning.\n"）;
printf（"jobisterminated.\n"）;
}
for（j=1;j<100000;j++）;
setfree（）;
adjust（）;
print（）;
printf（"isthereanyjobthatiswaiting?
y/n:
"）;
end=getchar（）;
}
}
voidxunhuan（）
{
intapplyarea,i=0,j;
charend;
getchar（）;
printf（"\nisthereanyjobrequestmemory?
yorn:
"）;
while（（end=getchar（））=='y'）
{
printf（"atfirstthefreememoryisthis:
\n"）;
adjust（）;
print（）;
printf（"inputrequestmemorysize:
"）;
scanf（"%d",&applyarea）;
if（i==N-1）
{
i=alloc2（applyarea,i）;
if（i==-1）i=0;
}
elseif（ii=alloc2（applyarea,i）;
if（i==-1）
printf（"thereisnofitmemory,pleasewait\n"）;
else
{
adjust（）;
printf（"afterallocation,thefreememoryisthis:
\n"）;
print（）;
printf（"job'smemorystartaddressis:
%d\n",start）;
printf（"jobsizeis:
%d\n",applyarea）;
printf（"jobisrunning.\n"）;
printf（"jobisterminated.\n"）;
}
for（j=1;j<100000;j++）;
setfree（）;
adjust（）;
print（）;
printf（"isthereanyjobthatiswaiting?
y/n:
"）;
end=getchar（）;
}
}
voidbest（）
{
intapplyarea,start,i,j;
charend;
getchar（）;
printf（"\nisthereanyjobrequestmemory?
yorn:
"）;
while（（end=getchar（））=='y'）
{
printf（"atfirstthefreememoryisthis:
\n"）;
adjust（）;
print（）;
printf（"inputrequestmemorysize:
"）;
scanf（"%d",&applyarea）;
start=alloc3（applyarea）;
if（start==-1）
printf（"thereisnofitmemory,pleasewait\n"）;
else
{
adjust（）;
printf（"afterallocation,thefreememoryisthis:
\n"）;
print（）;
printf（"job'smemorystartaddressis:
%d\n",start）;
printf（"jobsizeis:
%d\n",applyarea）;
printf（"jobisrunning.\n"）;
printf（"jobisterminated.\n"）;
}
for（j=1;j<100000;j++）;
setfree（）;
adjust（）;
print（）;
printf（"isthereanyjobthatiswaiting?
y/n:
"）;
end=getchar（）;
}
}
main（）
{
chars;
printf（"choseonemethod:
a首次适应b循环首次c最佳适应\n"）;
s=getchar（）;
switch（s）
{
case'a':
shouci（）;
case'b':
xunhuan（）;
case'c':
best（）;
default:
printf（"error\n"）;
}
}
运行结果：
调试、编辑、运行程序，开始显示如图：
输入a，选择进行首次适应，然后输入y显示空闲区，显示如图：
再输入区间大小20，选择进行分配空间，作业开始运行，显示如图：
输入空闲区的开始地址1000，空闲区大小30，显示如图：
升级会员 