Question

USING C LANGUAGE

Write a program to compute a Caesar Cipher . You must read in a file of text and convert some of the letters to another letter using the following array:

char key[27] = “efghijklmnopqrstuvwxyzabcd”;

This means that if you encounter the letter ‘a’, then you will replace it with the letter ‘e’,etc. If you encounter any other characters in the input file (example: ‘A’ or space, etc,

you will write them as is.

You will write each line of the text (unencrypted and encrypted) to another text file

Answer 1

`Hey,

Note: If you have any queries related the answer please do comment. I would be very happy to resolve all your queries.

Please note to run there should be a file named unencrypted.txt in your current directory

#include <stdio.h>
#include<stdlib.h>
#include<string.h>
int main()
{

FILE* filePointer;
int bufferLength = 255;
char buffer[bufferLength];
FILE *fptr;
fptr = fopen("encrypted.txt","w");
if(fptr == NULL)
{
printf("Error!");   
exit(1);   
}
filePointer = fopen("unencrypted.txt", "r");

while(fgets(buffer, bufferLength, filePointer)) {
int n=strlen(buffer),i;
char key[27] = "efghijklmnopqrstuvwxyzabcd";
for(i=0;i<n;i++)
{
int a=buffer[i]-'a';
if(a<26)
{
buffer[i]=key[a];
}
  
}
printf("%s\n",buffer);
fprintf(fptr,"%s\n",buffer);

}
fclose(fptr);

fclose(filePointer);
/*
char* ch=readcontent("unencrypted.txt");

*/
return 0;
}

Kindly revert for any queries

Thanks.