1b.c

liunx下的shell实现；进程、线程同步的实现；I/O系统调用的比较（mmap）——操作系统的课程设计

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 1024
struct buffer
{
char buff[N];
struct buffer *next;
};
int main(void)
{
void shuchu(struct buffer *q,int j);
FILE *fpin;
struct buffer *head=NULL,*p;
int i=1,j;
fpin=fopen("text","rb");
if(fpin==NULL)
{
printf("can't open this file\n");
return 1;
}
while(i)
{
p=(struct buffer*)malloc(sizeof(struct buffer));
if(head==NULL)
{p->next=NULL;head=p;}
else
{
p->next=head;
head=p;
}
j=i;
i=fread(p->buff,sizeof(char),N,fpin);
}
fclose(fpin);
shuchu(head,j);
} 
void shuchu(struct buffer *q,int j)
{
FILE *fpout;
int i,flag=0;
char temp[N];
fpout=fopen("text","wb");
do
{
for(i=N-1;i>=0;i--)
{
temp[N-i-1]=q->buff[i];
}
q=q->next;
if(flag==0)
{
fwrite(temp+1024-j,sizeof(char),j,fpout);
flag=1;
}
else
{
fwrite(temp,sizeof(char),N,fpout);
}
}while(q!=NULL);
fclose(fpout);
}