text: #include <stdio.h> 
  #include <stdlib.h>
  #include <string.h>  
  
  #define BUFFSIZE 255
  
  void main (int argc, char* argv[]) 
  {
     	FILE *fp,*fq;
     	int  i,n;
    	char buffer[BUFFSIZE];
  
     	/* Open the source file in read mode */
   	fp = fopen (argv [1],"r");
    	if (fp == NULL) {
      		printf("%s file does not exist\n", argv[1]);
      		exit(1); 
    	} 
  
     	/* Create the destination file.  */ 
  	fq = fopen (argv[2], "w"); 
    	if (fq == NULL) {
       		perror ("An error occurred in creating the file\n"); 
      		exit(1); 
    	} 
    	while (!feof(fp))
    	{
      		fgets(buffer, BUFFSIZE, fp); 
      		n=strlen(buffer);
      		for(i=0;i<n;i++)
  			buffer[i]=buffer[i]-45;
  	      	fputs(buffer,fq);
    	}
     	fclose (fp); 
     	fclose (fq);  
  } 
  