Цезарь Шифр ​​объектно-ориентированное программирование

Одна проблема, которая стоит передо мной, это то, что вы проверяете текущий символ сообщения

if (aOriginalMessage[i] == fLowerCase[j] || aOriginalMessage[i] == fUpperCase[j])

потенциально после того, как изменил его с вашей сменой.

aOriginalMessage[i]++;

так как вы перебираете все возможные символы. Вы можете сохранить зашифрованное сообщение в другой переменной.

Кроме того, может быть более эффективным сначала сместить весь алфавит, а затем непосредственно назначить смещенные символы для зашифрованного сообщения.

Надеюсь, это поможет.

Ниже приведен код C ++, который я тестировал, и я снова повторяю, что он работает как для шифрования, так и для дешифрования …. то есть логика в порядке …

#include<iostream>
#include<string>

using namespace std;

string Encrypt(string&, int &);// Function Prototype.  This declares Encrypt to be a function that needs one variable as string and another as interger as arguments. Reference operator & in prototype
string Decrypt(string&, int &);//Function Prototype.  This declares Decrypt to be a function that needs one variable as string and another as interger as arguments. Reference operator & in prototype

int main()
{

string text;//the string that holds the user input

int key;//key holds the number by which the user wants the alphabets to be shifted

cout << "Enter your phrase: " << endl;
getline(cin, text);//gets the user input ( including spaces and saves it to the variable text)

cout << "Please choose a number(key) for which you wants the alphabets to be shifted:  " << endl;
/*Note: the key can either be positive (forward shifting), negative (backward shifting) or zero (no shifting)*/

cin >> key;//User input for number by which alphabets are going to be shifted

string kolo = Encrypt(text, key);

cout << "Encrypted Message: " << kolo << endl;//Function call to display encrypted message

//Decrypt(Encrypt(text, key), key);

cout << "Decrypted Message: " << Decrypt(kolo, key)<< endl;//Function call to display decrypted message

//system("Pause");

return 0;
}string Encrypt(string& Source, int& c)
{
char fUpperCase[26] = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };//Initialization of class member
char fLowerCase[26] = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z' };//Initialization of class member

int z;//z holds the value (int) of the length of the user input ( including spaces)
z = (int)Source.length();   /*give the variable z the value of the user input length and length is normally an unsigned long integer hence
we have to typecast it*/

/*counter that makes it keep looping until it "encrypts" all of the user input (that's why it keeps looping while its less than z)*/
for (int i = 0; i < z; i++)
{
for (int j = 0; j < 26; j++)
{
if (Source[i] == fLowerCase[j] || Source[i] == fUpperCase[j])
{
//text[i] = fLowerCase[j];

if (c > 0)
{
//another counter that loops forwards key times by incrementing method
for (int counter = 0; counter < c; counter++)
{
/*it checks if the letter text[x] is 'z' and if it is 'z' it will make it 'a'*/
if (Source[i] == 'z')
{
Source[i] = 'a';
}

else if (Source[i] == 'Z')
{
Source[i] = 'A';
}

else
{
Source[i]++;
}

}
}

else    if (c < 0)
{
//another counter that loops backwards key times by decrementing method
for (int counter = 0; counter < abs(c); counter++)
{
/*it checks if the letter text[x] is 'a' and if it is 'a' it will make it 'z'*/
if (Source[i] == 'a')
{
Source[i] = 'z';
}

else if (Source[i] == 'A')
{
Source[i] = 'Z';
}

else
{
Source[i]--;
}
}
}

else
{
Source[i];//No alphabet shifts
}

}

else {
continue;
}

break;
}

}

return Source;
}

string Decrypt(string& EncryptedMessage, int& c)
{
int y;//z holds the value (int) of the length of the user input ( including spaces)
y = (int)EncryptedMessage.length(); /*give the variable z the value of the user input length and length is normally an unsigned long integer hence
we have to typecast it*/for (int i = 0; i < y; i++)
{

if (isalpha(EncryptedMessage[i]))//verify if the all members of the encrypted message is alphabet if not the same special character is return whereas if it is alphabet it is eitther incremented or decremented
{

if (c > 0)
{
//another counter that loops forwards key times by incrementing method
for (int counter = 0; counter < c; counter++)
{
/*it checks if the letter text[x] is 'a' and if it is 'z' it will make it 'a'*/
if (EncryptedMessage[i] == 'a')
{
EncryptedMessage[i] = 'z';
}

else if (EncryptedMessage[i] == 'A')
{
EncryptedMessage[i] = 'Z';
}

else
{
EncryptedMessage[i]--;
}

}
}

else    if (c < 0)
{
//another counter that loops backwards key times by decrementing method
for (int counter = 0; counter < abs(c); counter++)
{
//it checks if the letter text[x] is 'a' and if it is 'a' it will make it 'z'
if (EncryptedMessage[i] == 'z')
{
EncryptedMessage[i] = 'a';
}

else if (EncryptedMessage[i] == 'Z')
{
EncryptedMessage[i] = 'A';
}

else
{
EncryptedMessage[i]++;
}
}
}

else
{
EncryptedMessage[i];//No alphabet shifts
}

}

//cout << "Decrypted Message: " << EncryptedMessage << endl;//Function call to display decrypted message}
return EncryptedMessage;
}

Измените код конструктора на:

CyclicShift::CyclicShift()
{
static char const fUpper[26] = { 'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z' };//Initialization of class member
static char const fLower[26] = { 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z' };//Initialization of class member

strcpy_s(fUpperCase, fUpper);
strcpy_s(fLowerCase, fLower);
}

Я изменил длину массивов символов на 27, чтобы избежать переполнения буфера.

char fUpperCase[27];//A-Z
char fLowerCase[27];//a-z