主存空间的分配实验.doc

1.采用可变分区管理，使用首次适应算法实现主存的分配与回收 #include iostream #include memory.h #include vector #include algorithm #include time.h using namespace std; struct block{ //定义空闲块的记录表; int begin; int length; }; bool cmp(const block p1,const block p2){ if(p1.beginp2.begin) return true; return false; } vectorblock mem_table; vectorblock free_table; void init(){ //初始化空闲块,并将空闲信息记录到空闲分区说明表中; block now; while(cinnow.beginnow.length,now.begin=0){ mem_table.push_back(now); } sort(mem_table.begin(),mem_table.end(),cmp); if(mem_table[0].begin0){ now.begin=0; now.length=mem_table[0].begin; free_table.push_back(now); } vectorblock::iterator p=mem_table.begin(); while(p!=mem_table.end()p+1!=mem_table.end()){ if(p-begin+p-length(p+1)-begin){ now.begin=p-begin+p-length; now.length=(p+1)-begin-now.begin; free_table.push_back(now); } p++; } if(mem_table[mem_table.size()-1].begin+mem_table[mem_table.size()-1].length256){ now.begin=mem_table[mem_table.size()-1].begin+mem_table[mem_table.size()-1].length; now.length=256-now.begin; free_table.push_back(now); } sort(free_table.begin(),free_table.end(),cmp); } void applacation(const int lenght){ //内存申请操作; vectorblock::iterator p=free_table.begin(); while(p!=free_table.end()){ if(p-length=lenght){ block now; now.begin=p-begin; now.length=lenght; mem_table.push_back(now); if(p-length==lenght) //查找成功就将内存分配出去; free_table.erase(p); else { p-begin+=lenght; p-length-=lenght; } cout分配成功!endl; return ; } p++; } cout内存不够,无法分配endl; exit(0); } void print(){ //主存空间占用表和空闲分区说明表的打印; cout主存空间占用情况endl 起始地址 长度endlendl; for(int i=0;imem_table.size();i++) coutmem_table[i].begin mem_table[i].lengthendl; coutendl 空闲区表endl 起始地址 长度endl; for(int i=0;ifree_table.size();i++) coutfree_table[i].begin free_table[i].lengthendl; } void recover(){ //内存的回收; int t; t=rand()%mem_table.size(); //随机选取一个非系统内存块进行回收; while(t==0) t=rand()%mem_table