CODER.C

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

void loadFile();
void processFile(int);
char txtfile[512];
int recordsize=22;
char id[9];

char inFileName[12];
char outFileName[12];
void viewContents();
void saveFile();

FILE *open_file(char*, char*);

int fileLoaded=0;
int numrecords=0;
int fileEncrypted=0;
int currentrec=0;

int main ()
{

  char option = '0';

  id[0]= '7';
  id[1]='6';
  id[2]='4';
  id[3]='5';
  id[4]='8';
  id[5]='2';
  id[6]='5';
  id[7]='1';
  id[8]='2';
  id[9]=0;

  while (option !='X')
  {
    system("cls");
	printf("File Accessed:");
	if (fileLoaded==1)
		printf("%s\n",inFileName);
	else
		printf("None\n");

	printf("[L]oad a file\n");
	if (fileLoaded==1)
	{
		printf("[V]iew contents\n");
		if (fileEncrypted==0)
			printf("[E]ncrypt file\n");
		else
			printf("[D]ecrypt file\n");
		printf("[S]ave file\n");
	}
	printf("E[X]it\n");
	option =getchar();
	switch(option)
		{
		case 'L':case'l':{loadFile();
			  break;
			  }
		case 'V':case'v':{viewContents();
			 break;
			 }
		case 'E':case'e':{processFile(1);
			 break;
			 }
		case 'D':case'd':{processFile(0);
			  break;
			  }
		case 'S':case's':{saveFile();
			  break;
			 }
		}


	}
	/*end of while statement*/
	printf("End of program\n");
  }  /*end main*/

 void loadFile()
 {
  int ch=0;
  int filepos = 0;
  FILE *in;

  printf("Please input file name:");
  scanf("%s",inFileName);

  /*
  char ext[3];
  for(int=0;i<2;i++)
  {
                    ext[i]=inFileName[9+i];
  }
  if ext=='enc'
                    
  */

  numrecords =1;
  in = open_file (inFileName, "r" );

  while((ch=fgetc(in))!=EOF)
  {     txtfile[filepos]=ch;
	if (ch=='\n')
		numrecords++;
	filepos++;
  }

  fclose ( in );
  fileLoaded = 1;
  printf("File has been loaded\n");
  printf("Hit the enter key to continue\n");
  while (!(kbhit()));


}
 /*end of loadfile*/


 FILE *open_file ( char *file, char *mode )
{
  FILE *fp = fopen ( file, mode );

  if ( fp == NULL ) {
    perror ( "Unable to open file" );
    exit ( EXIT_FAILURE );
  }

  return fp;
}

void viewContents()
{
int total=0,num;
char strint[3];
/* for(currentrec=0;currentrec<=numrecords;currentrec++)*/
currentrec = 0;

printf("===========================================\n");
printf("\tFile Contents\t\t\n");
printf("===========================================\n");

while (currentrec < numrecords)
{ printf("%.*s\n",recordsize, txtfile+(currentrec*(recordsize+1)));
  strint[0]= txtfile[20+(currentrec*(recordsize+1))];
  strint[1]=txtfile[21+(currentrec*(recordsize+1))];
  strint[2]=0;
  num=atoi(strint);
  total+=num;
  currentrec=currentrec+1;

}
if (fileEncrypted==0)
{

	printf("File Totals\t:");
	printf("%d\n",total);

}
 /*print contents, 22 characters at a time*/
 /*for each row, convert last two digits to integer*/
 /*print footer at the end*/
printf("Hit the enter key to continue\n");
while (!(kbhit()));


}

void processFile(int mode)
{
    int i,shiftval;
    currentrec = 0;
	if(mode==1)
    {
     while (currentrec < numrecords)
	 {
          
		for ( i= 0; i <= recordsize-1;i++)
			{
				shiftval = id[i % 9]-48;
				txtfile[i + currentrec*(recordsize+1)]= txtfile[i + currentrec*(recordsize+1)] - shiftval;
			}
		currentrec++;
	 }
	fileEncrypted= 1;
	printf("File contents have been encrypted\n");
    }
    else
    {
        if(mode==0)
        {
                    while (currentrec < numrecords)
	                {
          
		                  for ( i= 0; i <= recordsize-1;i++)
       			          {
				                   shiftval = id[i % 9]-48;
                                    txtfile[i + currentrec*(recordsize+1)]= txtfile[i + currentrec*(recordsize+1)] + shiftval;
                       }
		               currentrec++;
		               
	                 }
	                 fileEncrypted= 0;
	                 printf("File contents have been decrypted\n"); 
                  }
                  }              
	printf("Hit the enter key to continue\n");
	while (!(kbhit()));

}

void saveFile()
 {
     FILE *fptr;
  printf("Enter code that will save the file\n");
  fptr = open_file(inFileName,"w");
  if(fptr==NULL)
  {
                printf("File could not be opened\n");
                }
  else
  {
      fprintf(fptr,txtfile);
      fclose(fptr);
      
  }
 
  printf("Hit the enter key to continue\n");
  while (!(kbhit()));


}