#include<stdio.h>
#include<string.h>
#include<stdlib.h> 
#define LENGTH 81
int main()
{
	char mystr[LENGTH];
	int mychar=0;
	FILE *pfile=NULL;
	char *filename="myfile.txt";
	
	printf("Enter an interesting string of up to %d characters:\n",LENGTH-1);
	if(!fgets(mystr,LENGTH,stdin)) 
	{
		printf("Input from keyboard failed.\n");
		exit(1);
	}
	
	// Creat a new file we can wrrite
	if(fopen(filename,"w"))
	{
		printf("Error opening %s for writing.Program terminated.\n",filename);
		exit(1);
	}
	setvbuf(pfile,NULL,_IOFBF,BUFSIZ);
	for(int i=strnlen(mystr,LENGTH)-1;i>=0;--i)
	{
		fputc(mystr[i],pfile);
	}
	fclose(pfile);
	
	// Open the file for read
	if(fopen(filename,"r"))
	{
		printf("Error opening %s for reading .Program terminated.",filename);
		exit(1);
	}
	setvbuf(pfile,NULL,_IOFBF,BUFSIZ);
	
	// Read a charcaters from the file and display it
	printf("the data read from the file is；\n");
	while((mychar=fgetc(pfile))!=EOF)
	{
		putchar(mychar);
	}
	fclose(pfile);
	pfile=NULL;
	remove(filename);
	return 0;
	
}