存储管理实验

实验目的

模拟存储管理中内存空间的管理和分配

存储管理的主要功能之一是合理地分配空间。内存空间的管理分为固定分区管理方式，可变分区管理方式，页式存储管理，段式存储管理。可以对这几种管理方式进行分配和回收的实验。

一、实验内容

以分区管理为例，程序功能为

1、完成分配内存的工作；

2、完成回收内存的工作；

3、显示主存的情况（包括已分配区和空闲区）。

二、程序流程图

主程序流程图：

主要函数模块流程图：

三、代码实现：

#include<stdio.h> #include<stdlib.h> /*因为下面用到内存动态分配函数*/ #define N 10 typedef struct memory { int order; int volume; int start_address; int alloc; int free; int state; }MEM; MEM * Create_memory( ); MEM * Alloction_memory( ); MEM * Recover_memory( ); void Output_memory( ); main( ) { char temp; int flag=0; /*用来标志最后一次分配的进程的记号，此变量存储该进程的序号order.*/ MEM *M=NULL; M=(MEM *)calloc(N,sizeof(MEM)); M=Create_memory(M); Output_memory(M); printf("Please input one char:'a'(Alloction_memory) or 'r'(Recover_memory)\nWhen you input 'z',then this program is over!\n"); //temp=getchar(); //getchar(); while(1) { temp=getchar(); //getchar(); if(temp=='z') { break; } if(temp=='a'||temp=='A') { M=Alloction_memory(M,&flag); } if(temp=='r'||temp=='R') { M=Recover_memory(M,&flag); //Output_memory(M); } printf("Please input one char:'a'(Alloction_memory) or 'r'(Recover_memory)\nWhen you input 'z',then this program is over!\n"); //temp=getchar(); //getchar();/*接受回车符！*/ } /*Alloction_memory(M); Recover_memory(M); printf("\n"); Output_memory(M);*/ } MEM * Create_memory(MEM *Create_M) { int i; for(i=0;i<N;i++) { Create_M[i].order=i+1; Create_M[i].volume=50+rand()%50; if(i==0) { Create_M[0].start_address=0; } else { Create_M[i].start_address=Create_M[i-1].start_address+Create_M[i-1].volume;/*首地址从0开始*/ } Create_M[i].alloc=0; Create_M[i].free=Create_M[i].volume; Create_M[i].state=0; } return Create_M; } MEM * Alloction_memory(MEM *Alloction_M,int *Alloction_flag) { int i,/*k=0,*/ask_volume; printf("This is Alloction_memory function!\nPlease input you will ask for the memory of volume!\n"); printf("Please input a integer,not other word!\nIf input is '-1',then Alloction_memory over!\n"); while(1) { scanf("%d",&ask_volume); if(ask_volume==-1) { getchar();/*输入的若是-1，用来接收回车，防止影响main()中的temp=getchar()语句。*/ break; } for(i=0;i<N;i++) { if(ask_volume<=Alloction_M[i].free) { Alloction_M[i].alloc=ask_volume; Alloction_M[i].free=Alloction_M[i].free-Alloction_M[i].alloc; Alloction_M[i].start_address=Alloction_M[i].start_address+ask_volume; Alloction_M[i].state=1; *Alloction_flag=Alloction_M[i].order; //k=1; //break; Output_memory(Alloction_M); Alloction_M[i].state=0; printf("You can alloc memory again!\nPlease input a integer,not other word!\nIf input is '-1',then Alloction_memory over!\n"); break; } } /*if(k==1) { break; }*/ if(i==N) { printf("\nThis alloc is fail!\nYou ask for the memory of volume,is above the max_memory!\nPlesase input the right volume again:\n"); } } return Alloction_M; } MEM * Recover_memory(MEM *Recover_M,int *Recover_flag) { int i; getchar(); //接受回车符。 for(i=0;i<N;i++) { if(/*(Recover_M[i].state==1)&&(Recover_M[i].free!=Recover_M[i].volume)*/*Recover_flag==Recover_M[i].order) { Recover_M[i].state=0; } else { if((Recover_M[i].state==0)&&(Recover_M[i].free!=Recover_M[i].volume)) { if(Recover_M[i].order==1) { Recover_M[i].start_address=0; } else { Recover_M[i].start_address=Recover_M[i-1].start_address+Recover_M[i-1].volume; } Recover_M[i].alloc=0; Recover_M[i].free=Recover_M[i].volume; Recover_M[i].state=1; } } } Output_memory(Recover_M); for(i=0;i<N;i++) { /*if(Recover_M[i].free!=Recover_M[i].volume) { Recover_M[i].state=1; } else {*/ Recover_M[i].state=0; //} } //free(Recover_M); return Recover_M; } void Output_memory(MEM *Output_M) { int i; printf("Order\tVolume\tstart_address\talloc\tfree\tstate\n"); for(i=0;i<N;i++) { printf("%d\t%dkb\t%dkb\t\t%dkb\t%dkb\t%d\n",Output_M[i].order,Output_M[i].volume,Output_M[i].start_address,Output_M[i].alloc,Output_M[i].free,Output_M[i].state); } }

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