0617 主存空间的分配和回收

#include <stdio.h> 
#include <stdlib.h> 
#include<string.h>
#include <conio.h> 
#define MAX 24
#define RAM 512
#define SYSTEM 100
struct partition { 
       char pn[10]; 
       char status; 
       int begin; 
       int size; 
       int end; 
}; 
typedef struct partition PART; 

PART ram[MAX];

//打印
void OutputPart()
{
    int i = 0;
    printf("空闲区表FREE：\n");
    while(i<MAX)
    {
        if(ram[i].status == ‘f‘)
        {
            printf("\n\tID\t开始\t空间\t结束\t状态\n");
            printf("No.%d\t%s\t%d\t%d\t%d\t%c\n",i+1,ram[i].pn,ram[i].begin,ram[i].size,ram[i].end,ram[i].status);
        }
        i++;

    }
    i = 0;
    printf("\n\n\n已分配区表USER：\n");
    while(i<24)
    {
        if(ram[i].status == ‘u‘)
        {
            printf("\n\tID\t开始\t空间\t结束\t状态\n");
            printf("No.%d\t%s\t%d\t%d\t%d\t%c\n",i+1,ram[i].pn,ram[i].begin,ram[i].size,ram[i].end,ram[i].status);
        }
        i++;
    }
    printf("\n\n");
}


//回收
void RecycleRAM()
{
    //回收内存的时候要先判断在空间当中前后是否有空闲区间。
    char name[10];
    int i = 0;

    //当空闲表单中，作业前面有空闲区间时
    printf("\n请输入要回收的作业的ID：");
    scanf("%s",&name);
    while(i < MAX)
    {
        if(strcmp(name,ram[i].pn)==0)
        {
            printf("找到任务%d！！！\n",i);
            if(i != 0 && i<MAX)
            {
                if(ram[i-1].status == ‘f‘ && ram[i+1].status == ‘f‘)
                {

                    //合并前后两个分区
                    ram[i-1].end = ram[i+1].end;
                    ram[i-1].size = ram[i-1].size + ram[i].size + ram[i+1].size;
                    ram[i-1].status = ‘f‘;
                    for(int j = i ; j<MAX ; j++)   //
                    {
                        if(j+2 < MAX)
                            ram[j] = ram[j+2];
                    }
                }

            }
            if(ram[i-1].status == ‘f‘ && ram[i+1].status != ‘f‘)
            {
                ram[i-1].end = ram[i].end;
                ram[i-1].size = ram[i-1].size + ram[i].size;
                ram[i-1].status = ‘f‘;
                for(int j = i ; j<MAX ; j++)
                {
                    if(j+1 <MAX)
                    {
                        ram[j] = ram[j+1];
                    }
                }
            }
            else if(ram[i-1].status != ‘f‘ && ram[i+1].status == ‘f‘)
            {
                ram[i].end = ram[i+1].end;
                ram[i].size = ram[i].size + ram[i+1].size;
                ram[i].status = ‘f‘;
                for(int j = i+1 ; j<MAX ; j++)
                {
                    if(j+1 < MAX)
                    {
                        ram[j] = ram[j+1];
                    }
                }
            }
            else if(ram[i-1].status != ‘f‘ && ram[i+1].status != ‘f‘)
            {                                                
                strcpy(ram[1].pn, "------");
                ram[i].status = ‘f‘;

            }
        }
        i++;
    }
}

//算法选择
void InputPart()
{
//    int bad;
    int best = 512;
    int bflag = 0;
    int i=0;
    int flag ;
    char name[10];
    int size;
    int j = MAX-1;
    printf("\n*********************");
    printf("\n1.首次适应算法");
    printf("\n2.最佳适应算法");
   // printf("\n3.最坏适应算法\n");
    printf("\n*********************\n");
    printf("请选择： ");
    scanf("%d",&flag);
    printf("\n\n请输入任务名：");
    scanf("%s",&name);
aa:   printf("请输入需要空间：");
   scanf("%d",&size);
    if(size>512){
        printf("输入空间过大！\n");
        goto aa;
    }
    switch(flag)
    {
    case 1://首次适应算法
        while(i<MAX)
        {
            if(ram[i].status == ‘f‘ && ram[i].size >= size)
            {
                //剩下公式！
                while(j>=i)
                {
                    ram[j] = ram[j-1];
                    j--;
                }
                strcpy(ram[i].pn, name);
                ram[i].begin = ram[i-1].end;
                ram[i].size = size;
                ram[i].end = ram[i].begin + ram[i].size;
                ram[i].status = ‘u‘;

                ram[i+1].begin = ram[i].end;
                ram[i+1].size = ram[i+1].size - ram[i].size;
                break;

            }
            i++;
        }
        break;
    case 2://最佳适应算法
        j = MAX;
        i=0;
        while(i<MAX)
        {
            if(ram[i].status == ‘f‘)
            {
                if(best > ram[i].size)
                {
                    best = ram[i].size;
                    bflag = i;
                }
            }
            i++;
        }
        if(ram[bflag].status == ‘f‘ && ram[bflag].size >= size)
        {
            //剩下公式！
            while(j>=bflag)
            {
                ram[j] = ram[j-1];
                j--;
            }
            strcpy(ram[bflag].pn, name);
            ram[bflag].begin = ram[bflag-1].end;
            ram[bflag].size = size;
            ram[bflag].end = ram[bflag].begin + ram[bflag].size;
            ram[bflag].status = ‘u‘;

            ram[bflag+1].begin = ram[bflag].end;
            ram[bflag+1].size = ram[bflag+1].size - ram[bflag].size;
        }
        break;
    }

}




void main()
{
    int flag;
    strcpy(ram[0].pn, "SYSTEM");
    ram[0].begin = 0;
    ram[0].size = SYSTEM;
    ram[0].end = ram[0].begin + ram[0].size;
    ram[0].status = ‘u‘;

    strcpy(ram[1].pn, "-----");
    ram[1].begin = ram[0].end;
    ram[1].size = RAM - ram[0].size;
    ram[1].end = RAM;
    ram[1].status = ‘f‘;

    printf("初始化，设内存总量为512K\n");
    printf("系统从低地址部分开始使用，占用100K\n\n");

    OutputPart();
    while(1)
    {
        printf("\n*********************");
        printf("\n1.添加任务");
        printf("\n2.收回内存");
        printf("\n3.显示任务\n");
        printf("*********************\n");
        printf("请选择： ");
        scanf("%d",&flag);
        switch(flag)
        {
        case 1:
            InputPart();
            break;
        case 2:
            RecycleRAM();
            break;
        case 3:
            OutputPart();
            break;
        }
    }
    
}