可变分区存储管理方式的内存分配和回收

1、#include<stdio.h>/定义输入/输出函数#include<iostream.h>/数据流输入/输出 #include<string.h>/字符串处理#include<iomanip.h>/参数化输入/输出const int MJ=10;/假定系统允许的最大作业数量为10typedef struct nodeint address;int length;char tag10;job;job freesMJ;int free_quantity;job occupysMJ;int occupy_quantity;int read()FIL

2、E *fp;char fn10;cout<<"请输入初始空闲表文件名:"cin>>fn;if(fp=fopen(fn,"r")=NULL) 其意义是在当前目录下打开文件file a，只允许进行“读”操作，并使fp指向该文件cout<<"错误,文件打不开,请检查文件名"<<endl;elsewhile(!feof(fp)fscanf(fp,"%d,%d",&freesfree_quantity.address,&freesfree_quantity.le

3、ngth);free_quantity+; fscanf(文件指针，格式字符串，输入表列)；return 1;return 0;void sort()int i,j,p;for(i=0;i<free_quantity-1;i+)p=i;for(j=i+1;j<free_quantity;j+)if(freesj.address<freesp.address)p=j;if(p!=i)freesfree_quantity=freesi;freesi=freesp;freesp=freesfree_quantity;void view()int i;cout<<endl

4、<<"mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm"<<endl;cout<<"输出空闲区表：n起始地址 分区长度 状态n"<<endl;for(i=0;i<free_quantity;i+)cout.setf(2);cout.width(12);cout<<freesi.address;cout.width(10);cout<<freesi.length;cout.width(8);cout<&l

5、t;freesi.tag<<endl;cout<<endl<<"wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww"<<endl;cout<<"输出已分分区表：n起始地址 分区长度 占用作业名n"<<endl;for(i=0;i<occupy_quantity;i+)cout.setf(2);cout.width(12);cout<<occupysi.address;cout.width(10);

6、cout<<occupysi.length;cout.width(8);cout<<occupysi.tag<<endl;void ear()char job_name10;int job_length;int i,j,flag,t;cout<<"请输入分配内存的作业名和空间大小:"cin>>job_name;cin>>job_length;flag=0;for(i=0;i<free_quantity;i+) /寻找空间大于作业的空闲区登记项if(freesi.length>=job_len

7、gth)flag=1;if(flag=0) /未找到空闲区，返回cout<<endl<<"无可用的空闲区n"<<endl;elset=0;i=0;while(t=0)if(freesi.length>=job_length)/找到可用空闲区，开始分配t=1;i+;i-;occupysoccupy_quantity.address=freesi.address; /修改已分配区表 strcpy(occupysoccupy_quantity.tag,job_name);occupysoccupy_quantity.length=job_

8、length;occupy_quantity+;if(freesi.length>job_length)freesi.address+=job_length;freesi.length-=job_length;elsefor(j=i;j<free_quantity-1;j+)freesj=freesj+1;free_quantity-;cout<<"内存空间成功:)"<<endl; void reclaim()/回收作业所占的内存空间char job_name20;int i,j,flag,p=0;int address;int leng

9、th;/寻找已分分区表中对应的登记项cout<<"输入要回收分区的作业名:"cin>>job_name;flag=-1;for(i=0;i<occupy_quantity;i+)if(!strcmp(occupysi.tag,job_name)flag=i;address=occupysi.address;length=occupysi.length;if(flag=-1) /在已分分区表中找不到作业cout<<"没有这个作业名"<<endl;else/修改空闲区表，加入空闲表for(i=0;i<

10、;free_quantity;i+)if(freesi.address+freesi.length)=address)if(i+1)<free_quantity)&&(freesi+1.address=address+length)freesi.length=freesi.length+freesi+1.length+length;for(j=i+1;j<free_quantity;j+)freesj=freesj+1;free_quantity-;p=1;elsefreesi.length+=length;p=1;if(freesi.address=(addres

11、s+length)freesi.address=address;freesi.length+=length;p=1;if(p=0)freesfree_quantity.address=address;freesfree_quantity.length=length;free_quantity+;/删除分配表中的该作业for(i=flag;i<occupy_quantity;i+)occupysi=occupysi+1;occupy_quantity-;void main()int flag=0;int t=1;int chioce=0;int i;for(i=0;i<MJ;i+)f

12、reesi.address=-1;/空闲区表初始化freesi.length=0;strcpy(freesi.tag,"free");occupysi.address=-1;/已分分区表初始化occupysi.length=0;strcpy(occupysi.tag,"");free_quantity=0;occupy_quantity=0;flag=read();while(flag=1)sort();cout<<"选择功能项: （0-退出，1-分配内存，2-回收内存，3-显示内存）n"<<endl;cout<<&