IO文件

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fputc fgetc 可以用来读写文件中的一个字符

1.一批数据是以文件的形式存放在外部介质中，

2.操作系统是以文件为单位对数据进行管理的！

3.把一个字符写到磁盘上去！

fputc(ch,fp);

函数的作用是将字符（ch的值）输出到fp所指的文件中去！

#define 　　putchar(c) 　　 fputc(c,stdout)

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

int main()
{
FILE *fp;
char ch,filename[10];
printf("Please input you create file name/n");
scanf("%s",filename);
getchar();
if((fp=fopen(filename,"w"))==NULL)
{
printf("can not open file/n");
exit(0);
}

printf("Please input Content/n");
ch=getchar();
while(ch!='#')
{
  fputc(ch,fp);
  ch=getchar();
}

putchar(10);
fclose(fp);

return 0;
}

4.从指定的文件读入一个字符该文件必须是以读或以读写的方式打开，

ch=fgetc(fp);

while(ch!=EOF)

{

ch=fgetc(fp);

}

函数feof(fp)

判断文件是否真的结束：

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

int main()
{
FILE *in,*out;
char ch,infile[10],outfile[10];

printf("Enter the infile name:/n");
scanf("%s",infile);

printf("Enter the outfile name/n");
scanf("%s",outfile);

if((in=fopen(infile,"r"))==NULL)
{
  printf("can not open file/n");
  exit(0);
}

if((out=fopen(outfile,"r"))==NULL)
{
  printf("can not open file/n");
  exit(0);
}

while(!feof(in))
{
fputc(fgetc(in),out);
}

fclose(in);
fclose(out);

return 0;
}

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

int main(int argc,char *argv[])
{
FILE *in,*out;

if(argc!=3)
{
printf("You forgot to enter a filename/n");
exit(0);
}

if((in=fopen(argv[1],"r"))==NULL)
{
  printf("cannot open infile/n");
  exit(0);
}
if((out=fopen(argv[2],"w"))==NULL)
{
  printf("cannot open outfile/n");
  exit(0);
}
while(!feof(in))
{
  fputc(fgetc(in),out);
}
fclose(in);
fclose(out);
return 0;
}
执行过程就不用说啦！自己想吧！

fread 　　fwrite(读写一个数据块)

#include<stdio.h>
#include<stdlib.h>
#define SIZE 2

struct student_type
{
char name[10];
int num;
int age;
char addr[15];
}stud[SIZE];

void save()
{
FILE *fp;
int i;

if((fp=fopen("stu_list.c","wb"))==NULL)
{
  printf("cannot open file/n");
  return ;
}

for(i=0;i<SIZE;i++)
  if(fwrite(&stud[i],sizeof(struct student_type),1,fp)!=1)
   printf("file write error/n");
  fclose(fp);
}

void load()
{
int i;
FILE *fp;

if((fp=fopen("stu_list.c","rb"))==NULL)
{
  printf("cannot open infile/n");
}

for(i=0;i<SIZE;i++)
{
  if((fread(&stud[i],sizeof(struct student_type),1,fp))!=1)
  {
   if(feof(fp))
   {
    fclose(fp);
    return;
   }
   printf("file read error/n");
  }
}
fclose(fp);
}

int main()
{
int i;

printf("Please input student Name Num Age Addr/n");
for(i=0;i<SIZE;i++)
{
scanf("%s%d%d%s",stud[i].name,&stud[i].num,&stud[i].age,stud[i].addr);
}

save();
load();
return 0;
}