Help with this substitution program, line 3 of the output is different than it should be and I
can't find the reaso why. Here's the code, the input file, and the output file.
#include "cipher.h"
/* Cheshire smile implementation.
It only contains the cipher alphabet
*/
struct Cipher::CipherCheshire {
string cipher_alpha;
};
/* This function checks the cipher alphabet
to make sure it's valid
*/
bool is_valid_alpha(string alpha);
// -------------------------------------------------------
// Cipher implementation
/* Default constructor
This will actually not encrypt the input text
because it's using the unscrambled alphabet
*/
Cipher::Cipher()
{
// TODO: Implement this default constructor
smile = new CipherCheshire();
smile->cipher_alpha = "zyxwvutsrqponmlkjihgfedcba";
}
/* This constructor initiates the object with a
input cipher key
*/
Cipher::Cipher(string cipher_alpha)
{
// TODO: Implement this constructor
smile - new CipherCheshire();
if (is_valid_alpha(cipher_alpha)) {
smile->cipher_alpha = cipher_alpha;
} else {
cout << "Invalid alpha" << endl;
exit(EXIT_FAILURE);
}
}

/* Destructor
*/
Cipher::~Cipher()
{
// TODO: Implement this constructor
delete(smile);
}
/* This member function encrypts the input text
using the intialized cipher key
*/
string Cipher::encrypt(string raw)
{
cout << "Encrypting...";
string retStr = "";
char ch, tmp;
int pos;
int i;
int size = raw.length();
// TODO: Finish this function
for (i = 0; i < size; i++) {
tmp = ' ';
ch = raw.at(i);
if (ch != ' ') {
por = find_pos(smile->cipher_alpha, ch)
if (ch >= 65 && ch <= 90) {
tmp = 65 + pos;
} else {
tmp = 97 + pos;
}
}
retStr += tmp;
}
cout << "Done" << endl;
return retStr;
}
/* This member function decrypts the input text
using the intialized cipher key
*/
string Cipher::decrypt(string enc)
{
string retStr = "";

char ch, tmp;
int pos;
int i;
int size = enc.length();
cout << "Decrypting...";
// TODO: Finish this function
for (i = 0; i < size; i++) {
tmp = ' ';
ch = enc.at(i);
if (ch != ' ') {
pos = find_pos(smile->cipher_alpha, ch);
if (ch >= 65 && ch <= 90) {
tmp = 65 + pos;
} else {
tmp = 97 + pos;
}
}
retStr += tmp;
}
cout << "Done" << endl;
return retStr;
}
// -------------------------------------------------------
// Helper functions
/* Find the character c's position in the cipher alphabet/key
*/
unsigned int find_pos(string alpha, char c)
{
unsigned int pos = 0;
int i;
int size = alpha.length();
// TODO: You will likely need this function. Finish it.
char ch = tolower(c);
for (i = 0; i < size; i++) {
if (ch == alpha.at(i)) {
por = i;
break;
}
}

return pos;
}
/* Make sure the cipher alphabet is valid -
a) it must contain every letter in the alphabet
b) it must contain only one of each letter
c) it must be all lower case letters
ALL of the above conditions must be met for the text to be a valid
cipher alphabet.
*/
bool is_valid_alpha(string alpha)
{
bool is_valid = true;
if(alpha.size() != ALPHABET_SIZE) {
is_valid = false;
} else {
unsigned int letter_exists[ALPHABET_SIZE];
for(unsigned int i = 0; i < ALPHABET_SIZE; i++) {
letter_exists[i] = 0;
}
for(unsigned int i = 0; i < alpha.size(); i++) {
char c = alpha[i];
if(!((c >= 'a') && (c <= 'z'))) {
is_valid = false;
} else {
letter_exists[(c - 'a')]++;
}
}
for(unsigned int i = 0; i < ALPHABET_SIZE; i++) {
if(letter_exists[i] != 1) {
is_valid = false;
}
}
}
return is_valid;
}
INPUT:
EXPECTED OUTPUT:
CURRENT OUTPUT:
zyxwvutsrqponmlkj ihgfedcba Sometimes it is the people no one can imagine anything of who
do the things no one can imagine Hlnvgrnvh rg rh gsv kvlkov ml lmv Xzm rnztrmv zmbgsrmt lu
dsl wl gsv gsrmth ml lmv Xzm rnztrmv Sometimes it is the people no one can imagine anything

of who do the things no one can imagine Sometimes it is the people no one can imagine anything
of who do the things no one can imagine Sometimes it is the people no one can imagine anything
of who do the things no one can imagine Hlnvgrnvh rg rh gsv kvlkov ml lmv xzm rnztrmv
zmbgsrmt lu dsl wl gsv gsrmth ml lmv xzm rnztrmv Sometimes it is the people no one can
imagine anything of who do the things no one can imagine Hlnvgrnvh rg rh gsv kvlkov ml lmv
Xzm rnztrmv zmbgsrmt lu dsl wl gsv gsrmth ml lmv Xzm rnztrmv Sometimes it is the people no
one can imagine anything of who do the things no one can imagine