Variable partition scheduling algorithm: the first to adapt to the allocation algorithm, the optimal allocation algorithm to adapt to the worst adaptation algorithm user application memory space; the system according to the applicant's request, in accordance with the use of certain memory space allocation policy analysis, to find out to meet the requests of the free zone, and give to the applicant; when the program is finished or memory resources initiative to return the system to recover memory space it occupies it or return of part of the memory space.
1. Receiving a first input Runtime: free area of the data file, including a plurality of rows, each row having two data items: the starting address, length (all integers), each of the data items separated by commas.
2. The establishment of free zones table and displayed on the screen output table of contents free zone, free zone table records the start address of memory available for distribution free area and length, indicate whether the partition is unallocated space area with a flag.
3. Receiving from the user interface prompts the user to apply a memory according to the format: job name, the size of the application space.
4. According to the worst (worst) adaptation algorithm to select a free area, divide and distribute, modify the corresponding data structures (table space area), fill in the allocated memory block table (the starting address, length, flag), wherein the flag one role is to point out that the area to which assigned jobs.
5. 3 and 4 is repeated, until the input is a special character (0).
6. New free zone display output tables and the contents of the allocated area table on the screen.
This program includes: FIFO, optimal allocation algorithm to adapt to the worst adaptation algorithm
The variable storage management
#include < stdio.h >
#include < iostream.h >
#include < string .h >
#include < iomanip.h >
const int MAXJOB = 100 ; // 定义表最大记录数
typedef struct node{
int start;
int length;
char tag[ 20 ];
}job;
job frees[MAXJOB]; // 定义空闲区表
int free_quantity;
job occupys[MAXJOB]; // 定义已分配区表
int occupy_quantity;
// 初始化函数
void initial()
{
int i;
for (i = 0 ;i < MAXJOB;i ++ ){
frees[i].start =- 1 ;
frees[i].length = 0 ;
strcpy(frees[i].tag, " free " );
occupys[i].start =- 1 ;
occupys[i].length = 0 ;
strcpy(occupys[i].tag, "" );
}
free_quantity = 0 ;
occupy_quantity = 0 ;
}
// 读数据函数
int readData()
{
FILE * fp;
char fname[ 20 ];
cout << " 请输入初始空闲表文件名: " ;
cin >> fname;
if ((fp = fopen(fname, " r " )) == NULL){
cout << " 错误,文件打不开,请检查文件名 " << endl;
}
else {
while ( ! feof(fp)){
fscanf(fp, " %d,%d " , & frees[free_quantity].start, & frees[free_quantity].length);
free_quantity ++ ;
}
return 1 ;
}
return 0 ;
}
// sort
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 (frees[j].start < frees[p].start){
p = j;
}
}
if (p != i){
frees[free_quantity] = frees[i];
frees[i] = frees[p];
frees[p] = frees[free_quantity];
}
}
}
// 显示函数
void view()
{
int i;
cout << endl << " ---------------------------------------------------------- " << endl;
cout << " 当前空闲表: " << endl;
cout << " 起始地址 长度 状态 " << endl;
for (i = 0 ;i < free_quantity;i ++ ){
cout.setf( 2 );
cout.width( 12 );
cout << frees[i].start;
cout.width( 10 );
cout << frees[i].length;
cout.width( 8 );
cout << frees[i].tag << endl;
}
cout << endl << " ---------------------------------------------------------- " << endl;
cout << " 当前已分配表: " << endl;
cout << " 起始地址 长度 占用作业名 " << endl;
for (i = 0 ;i < occupy_quantity;i ++ ){
cout.setf( 2 );
cout.width( 12 );
cout << occupys[i].start;
cout.width( 10 );
cout << occupys[i].length;
cout.width( 8 );
cout << occupys[i].tag << endl;
}
}
// 最先适应分配算法
void earliest()
{
char job_name[ 20 ];
int job_length;
int i,j,flag,t;
cout << " 请输入新申请内存空间的作业名和空间大小: " ;
cin >> job_name;
cin >> job_length;
flag = 0 ;
for (i = 0 ;i < free_quantity;i ++ ){
if (frees[i].length >= job_length){
flag = 1 ;
}
}
if (flag == 0 ){
cout << endl << " Sorry,当前没有能满足你申请长度的空闲内存,请稍候再试 " << endl;
}
else {
t = 0 ;
i = 0 ;
while (t == 0 ){
if (frees[i].length >= job_length){
t = 1 ;
}
i ++ ;
}
i -- ;
occupys[occupy_quantity].start = frees[i].start;
strcpy(occupys[occupy_quantity].tag,job_name);
occupys[occupy_quantity].length = job_length;
occupy_quantity ++ ;
if (frees[i].length > job_length){
frees[i].start += job_length;
frees[i].length -= job_length;
}
else {
for (j = i;j < free_quantity - 1 ;j ++ ){
frees[j] = frees[j + 1 ];
}
free_quantity -- ;
cout << " 内存空间成功:} " << endl;
}
}
}
// 最优适应分配算法
void excellent()
{
char job_name[ 20 ];
int job_length;
int i,j,flag,t;
cout << " 请输入新申请内存空间的作业名和空间大小: " ;
cin >> job_name;
cin >> job_length;
flag = 0 ;
for (i = 0 ;i < free_quantity;i ++ ){
if (frees[i].length >= job_length){
flag = 1 ;
}
}
if (flag == 0 ){
cout << endl << " Sorry,当前没有能满足你申请长度的空闲内存,请稍候再试 " << endl;
}
else {
t = 0 ;
i = 0 ;
while (t == 0 ){
if (frees[i].length >= job_length){
t = 1 ;
}
i ++ ;
}
i -- ;
for (j = 0 ;j < free_quantity;j ++ ){
if ((frees[j].length >= job_length) && (frees[j].length < frees[i].length)){
i = j;
}
}
occupys[occupy_quantity].start = frees[i].start;
strcpy(occupys[occupy_quantity].tag,job_name);
occupys[occupy_quantity].length = job_length;
occupy_quantity ++ ;
if (frees[i].length > job_length){
frees[i].start += job_length;
frees[i].length -= job_length;
}
else {
for (j = i;j < free_quantity - 1 ;j ++ ){
frees[j] = frees[j + 1 ];
}
free_quantity -- ;
cout << " 内存空间成功:) " << endl;
}
}
}
// 最坏适应算法
void worst()
{
char job_name[ 20 ];
int job_length;
int i,j,flag,t;
cout << " 请输入新申请内存空间的作业名和空间大小: " ;
cin >> job_name;
cin >> job_length;
flag = 0 ;
for (i = 0 ;i < free_quantity;i ++ ){
if (frees[i].length >= job_length){
flag = 1 ;
}
}
if (flag == 0 ){
cout << endl << " Sorry,当前没有能满足你申请长度的空闲内存,请稍候再试 " << endl;
}
else {
t = 0 ;
i = 0 ;
while (t == 0 ){
if (frees[i].length >= job_length){
t = 1 ;
}
i ++ ;
}
i -- ;
for (j = 0 ;j < free_quantity;j ++ ){
if ((frees[j].length >= job_length) && (frees[j].length > frees[i].length)){
i = j;
}
}
occupys[occupy_quantity].start = frees[i].start;
strcpy(occupys[occupy_quantity].tag,job_name);
occupys[occupy_quantity].length = job_length;
occupy_quantity ++ ;
if (frees[i].length > job_length){
frees[i].start += job_length;
frees[i].length -= job_length;
}
else {
for (j = i;j < free_quantity - 1 ;j ++ ){
frees[j] = frees[j + 1 ];
}
free_quantity -- ;
cout << " 内存空间成功:) " << endl;
}
}
}
// 撤消作业
void finished()
{
char job_name[ 20 ];
int i,j,flag,p = 0 ;
int start;
int length;
cout << " 请输入要撤消的作业名: " ;
cin >> job_name;
flag =- 1 ;
for (i = 0 ;i < occupy_quantity;i ++ ){
if ( ! strcmp(occupys[i].tag,job_name)){
flag = i;
start = occupys[i].start;
length = occupys[i].length;
}
}
if (flag ==- 1 ){
cout << " 没有这个作业名 " << endl;
}
else {
// 加入空闲表
for (i = 0 ;i < free_quantity;i ++ ){
if ((frees[i].start + frees[i].length) == start){
if (((i + 1 ) < free_quantity) && (frees[i + 1 ].start == start + length)){
frees[i].length = frees[i].length + frees[i + 1 ].length + length;
for (j = i + 1 ;j < free_quantity;j ++ ){
frees[j] = frees[j + 1 ];
}
free_quantity -- ;
p = 1 ;
}
else {
frees[i].length += length;
p = 1 ;
}
}
if (frees[i].start == (start + length)){
frees[i].start = start;
frees[i].length += length;
p = 1 ;
}
}
if (p == 0 ){
frees[free_quantity].start = start;
frees[free_quantity].length = length;
free_quantity ++ ;
}
// 删除分配表中的该作业
for (i = flag;i < occupy_quantity;i ++ ){
occupys[i] = occupys[i + 1 ];
}
occupy_quantity -- ;
}
}
// 显示版权信息函数
void version()
{
cout << endl << endl;
cout << " ┏━━━━━━━━━━━━━━━━━━━━━━━┓ " << endl;
cout << " ┃ 可变分区存储管理模拟系统 ┃ " << endl;
cout << " ┠───────────────────────┨ " << endl;
cout << " ┃ (c)All Right Reserved Neo ┃ " << endl;
cout << " ┃ [email protected] ┃ " << endl;
cout << " ┃ version 2004 build 1122 ┃ " << endl;
cout << " ┗━━━━━━━━━━━━━━━━━━━━━━━┛ " << endl;
cout << endl << endl;
}
void main()
{
int flag = 0 ;
int t = 1 ;
int chioce = 0 ;
version();
initial();
flag = readData();
while (flag == 1 ){
sort();
cout << endl << endl << " ========================================================= " << endl;
cout << " 可变分区存储管理模拟系统 " << endl;
cout << " ========================================================= " << endl;
cout << " 1.申请空间 2.撤消作业 3.显示空闲表和分配表 0.退出 " << endl;
cout << " 请选择: " ;
cin >> chioce;
switch (chioce){
case 1 :
// 换算法请换下一句调用
earliest();
break ;
case 2 :
finished();
break ;
case 3 :
view();
break ;
case 0 :
flag = 0 ;
break ;
default :
cout << " 选择错误! " << endl;
}
}
}
Reproduced in: https: //my.oschina.net/garyun/blog/602840