text: #include <stdio.h>
  #include <stdlib.h>
  
  #define FALSE 0
  #define TRUE 1
  
  int main(int argc, char **argv){
    //takes in a string or a file and create a output that has the appropriate parameters to run the Play-fair Cipher on this string/file
    char c;
    char last = 0;
    int counter = 0;
    while(scanf("%c", &c) != EOF){
      if(c == 74){ // J or j, will convert to I
        c = 73;
      } // if
      if(last == c && last != 0){ // add X between duplicates
        counter++;
        printf("%c",'X');
      } // if
      last = c;
      printf("%c", c);
      counter++; // add for every letter
    } // while
    if(counter % 2 != 0){ //if there are an odd number of letters including Xs, then add an X
      printf("%c", 'X');
    } // if
  } // main(int, char**)
  