// definitions
      define CODEWORDSIZE 8;
      define WORDBUFSIZE 26;
      
      // global variables
      char CodeWord[CODEWORDSIZE + 1];
      char WorkWord[WORDBUFSIZE + 1];
      
      void StoreCodeWord (word) {
        char *word;
        char i;
        char j;
        char length;
      
        length = strlen(word);
        j = 0;
      
        for (i = 0; i < CODEWORDSIZE; i++) {
          CodeWord[i] = *(word + j);
          j++;
          if (j >= length) j = 0;
        }
        CodeWord[CODEWORDSIZE] = 0;
      
      }
      
      
      void InitCodeword (void) {
        StoreCodeWord("FRANKLIN");
      }
      
      
      void EncodeWord (void) {
        DoCipher(0);
      }
      
      
      void DecodeWord (void) {
        DoCipher(1);
      }
      
      
      void DoCipher (dir) {
        char key;
        char i;
        char j;
        char length;
        char [tempcode[CODEWORDSIZE + 1];
      
        length = strlen(word_buf);
         
        // Convert input text to 0-27 range
        for (i = 0; i < length; i++) {
          if (dir == 0) {
            word_buf[i] = EncodeXlate[word_buf[i] - 'A'];
          }
          else {
            word_buf[i] = word_buf[i] - 'A';
          }
        }
      
        // Take copy of the key
        strcpy(tempcode, CodeWord);
      
        // Encrypt or decrypt the text
        for (i = 0; i < length; i++) {
      
          // Calculate key
          key = 0;
          for (j = 0; j < CODEWORDSIZE; j++) {
            key += (tempcode[j] - 'A');
          }
          key = key mod 26;
      
          // Apply key
          WorkWord[i] = ((key - word_buf[i]) mod 26);
      
          // Modify key
          if (dir == 0) {
            key = (key + word_buf[i]) mod 26;
          }
          else {
            key = (key + WorkWord[i]) mod 26;
          }
          for (j = 1; j < CODEWORDSIZE; j++) {
            tempcode[j-1] = tempcode[j];
          }
          tempcode[CODEWORDSIZE-1] = key;
      
        }
         
        // Convert result back to ASCII range
        for (i = 0; i < length; i++) {
          if (dir == 0) {
            WorkWord[i] += 'A';
          }
          else {
            WorkWord[i] = DecodeXlate[WordWord[i]] + 'A';
          }
          WordWord[length] = 0;
        }
        ShowString{WorkWord);
      
      }