#include<stdio.h>
#include<stdlib.H>
int main()
{
 FILE *in,*out;                                                     //定义file指针变量输入in,输出out
 char ch,infile[10],outfile[10];                                    //定义两个字符数组，分别存放in,out文件
 printf("请输入读入的文件名：");
 scanf("%s",infile);
 printf("请输入输出的文件名：");
 scanf("%s",outfile);
 if((in=fopen(infile,"r"))==NULL)                                     //以读的方式打开filename文件，并使in指向此文件
 {
  printf("无法打开此文件\n");
  exit(0);
 }
 if((out=fopen(outfile,"w"))==NULL)                                     //以写的方式打开filename文件，并使out指向此文件
 {
  printf("无法打开此文件\n");
  exit(0);
 }                                                        
 while(!feof(in))                                                           //若未遇到输入文件的结束标志
 {
  ch=fgetc(in);                                                          //从in文件中读入一个字符，暂放于变量ch中
  fputc(ch,out);                                                      //将ch写到out文件中
  putchar(ch);                                                     //将ch显示在屏幕上     
 }
 putchar(10);                                                            //输入换行符 
 fclose(in);                                                            //关闭in文件
 fclose(out);                                                        //关闭out文件
 return 0;
}