操作系统可变分区用C语言实现按最佳适应算法分配内存

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

typedef struct memory
{
int startaddress;
int size;
char state[10];
char number[10];
struct memory *next;
}FENQU;
FENQU *ready=NULL,*p;
FENQU * paixu(FENQU *p)
{
FENQU *first,*second;
int insert=0;
if((ready == NULL) || ((p->size) < (ready->size)))

{
p->next = ready;
ready = p;

}
else
{
first = ready;
second = first->next;
while (second != NULL)
{
if (p->size < second->size)
{
p->next = second;
first->next = p;
insert = 1;
break;
}
else
{
first = first->next;
second = second->next;
}
}
if (insert == 0)
{
first->next = p;
p->next = NULL;
}
}
return ready;
}
void show(FENQU *p)
{
printf("起始地址    大小      状态     进程号 \n");
printf("%5d\t",p->startaddress);
printf("%8d\t",p->size);
printf("%s  \t",p->state);
printf("%s  \t\n",p->number);

}
void input()
{
int i,address,size1,n=7;

for(i=1;i<=n;i++)
{
p=(FENQU*)malloc(sizeof(FENQU));
printf("请输入第%d个分区的起始地址：\n",i);
scanf("%d",&address);
p->startaddress=address;
printf("请输入第%d个分区的大小：\n",i);
scanf("%d",&size1);
p->size=size1;
printf("请输入第%d个分区的状态:\n",i);
scanf("%s",p->state);
printf("请输入第%i个分区的进程号：\n",i);
scanf("%s",p->number);
p->next=NULL;
paixu(p);
}
p = ready;
while (p != NULL)
{
show(p);
p = p->next;
}
}

void zjsy()
{
int asize,fazhi;
char pcbnumber;
//FENQU *a;
printf("请输入进程号，大小和阀值\n");
scanf("%s",&pcbnumber);
scanf("%d",&asize);
scanf("%d",&fazhi);
FENQU *pretail,*tail,*q;
p=ready;
pretail=tail=p;
while(tail!=NULL)
{

if(strcmp(tail->state,"空闲")==0 && tail->size>asize)
{
if(tail->size==asize)
{
strcpy(tail->number,&pcbnumber);
strcpy(tail->state,"已分");
break;

}

else  if(tail->size>asize)
{
q=(FENQU *)malloc(sizeof(FENQU));
q->startaddress=tail->startaddress+tail->size-asize;
q->size=asize;
strcpy(q->state,"已分");
strcpy(q->number,&pcbnumber);
q->next=tail->next;
tail->next=q;
tail->size = tail->size-asize;
strcpy(tail->number,"空闲");
strcpy(tail->number,"?");
break;
}

}

else
{
pretail=tail;
tail=tail->next;

}
}
if(tail==NULL)
{
printf("没有足够的空间，分配失败！\n");
}

pretail->next=tail->next;
tail->next=NULL;
p=paixu(tail);
}

FENQU * huishou()
{
char pcbnumber1;
printf("请输入被回收空间的进程号\n");
scanf("%s",&pcbnumber1);

FENQU *pretail,*tail;
p=ready;
pretail=tail=p;

while(tail!=NULL)
{
if(strcmp(tail->number,&pcbnumber1)==0)
{
if(tail->next!=NULL)
{
if(strcmp(pretail->state,"已分")==0 && strcmp(tail->next->state,"已分")==0)
{
strcpy(tail->state,"空闲");
strcpy(tail->number,"?");
break;

}
if(strcmp(pretail->state,"空闲")==0 && strcmp(tail->next->state,"已分")==0)
{
pretail->next=tail->next;
pretail->size=tail->size+pretail->size;
free(tail);
break;
}
if(strcmp(pretail->state,"已分")==0 && strcmp(tail->next->state,"空闲")==0)
{
if(pretail!=tail)
{
pretail->next=tail->next;
tail->next->size=tail->next->size+tail->size;
tail->next->startaddress=tail->startaddress;
free(tail);
break;

}
else
{
p=tail->next;
tail->next->startaddress=0;
tail->next->size+=tail->size;
break;
}

}
if(strcmp(pretail->state,"空闲")==0 && strcmp(tail->next->state,"空闲")==0)
{
pretail->next=tail->next->next;
pretail->size=pretail->size+tail->size+tail->next->size;
free(tail->next);
free(tail);
break;

}
}
else
{
if(strcmp(pretail->state,"已分")==0)
{
strcpy(tail->state,"空闲");
break;
}
else
{
pretail->next=NULL;
pretail->size=pretail->size+tail->size;
free(tail);
break;
}

}
}
pretail=tail;
tail=tail->next;
}
return p;
}

void function()
{
int i;
printf("请选择：(1) 分配空间 (2)回收空间  (3)结束\n");
scanf("%d",&i);
switch(i)
{
case 1:
zjsy();

printf("分配成功！\n");
while (p != NULL)
{
show(p);
p = p->next;
}
break;

case 2:
p=huishou();
while (p != NULL)
{
show(p);
p = p->next;
}
break;
case 3:
exit(0);
}
function();
}
void main()
{
input();
function();
}