/************************************************************************************************************************************************************************
* Encoder/Decoder
* Charles Wood-Henderson
* To encrypt strings and decrypt them.
* Acknowledgements: none
************************************************************************************************************************************************************************/
#include <iostream>
#include <string>
using namespace std;
/***********************************************************************************************************************************************************************
* cipher()
* none
* class
* To encode/decode strings.
************************************************************************************************************************************************************************/
class cipher {
private:
string line;
int shift_key;
bool encoder;
public:
cipher() : shift_key(0)
{ }
void get_shift_key();
void print();
void encode();
void decode();
};
/***********************************************************************************************************************************************************************
* main()
* none
* int
* Required to run the program.
***********************************************************************************************************************************************************************/
int main() {
cipher cipher1; // creating a class
string do_what; // creating a string to see what the user wants to do
bool repeat = true;
while(repeat == true) {
cout << "Welcome to the Caesar Encoder/Decoder!\n" << "Would you like to encode or decode or quit? ";
cin >> do_what;
if(do_what == "encode") {
cipher1.encode(); // seeing what the user wants to do
}
else if(do_what == "decode") {
cipher1.decode(); // seeing what the user wants to do
}
else if(do_what == "quit") { // seeing what the user wants to do
return 0;
}
}
}
void cipher::encode() {
encoder = true;
bool uppercase = false;
cout << "Please enter a string that you would like to encode: \n(Please end your string with a ~ symbol and then press the enter key)\n";
getline(cin, line, '~');
get_shift_key();
int length = line.length();
for(int j = 0; j < length; j++) {
if(line[j] >= 'A' && line[j] <= 'Z' || line[j] >= 'a' && line[j] <= 'z') {
if(line[j] < 'a')
uppercase = true;
else
uppercase = false;
line.at(j) = line.at(j) + shift_key; // shifting the letter how many places the user asked for
if(line.at(j) > 'z' && uppercase == false) {
int k = line.at(j) - 'z'; // checking if the places shifted goes over z when its lowercase
line.at(j) = 'a' + k - 1;
}
if(line.at(j) > 'Z' && uppercase == true) {
int k = line.at(j) - 'Z'; // checking if the places shifted goes over Z when its uppercase
line.at(j) = 'A' + k - 1;
}
}
}
print();
cout << endl;
}
void cipher::decode() {
encoder = false;
bool uppercase = false;
cout << "Please enter a string that you would like to encode: \n(Please end your string with a ~ symbol and then press the enter key)\n";
getline(cin, line, '~');
get_shift_key();
int length = line.length();
for(int j = 0; j < length; j++) {
if(line[j] >= 'A' && line[j] <= 'Z' || line[j] >= 'a' && line[j] <= 'z') {
if(line.at(j) < 'a')
uppercase = true;
else // checking if the letter is uppercase or lowercase
uppercase = false;
line.at(j) = line.at(j) - shift_key;
if(line.at(j) < 'a' && uppercase == false) {
int k = 'a' - line.at(j); // checking that the places needed to go backwards goes less than a in lowercase
line.at(j) = 'z' - k + 1;
}
if(line.at(j) < 'A' && uppercase == true) {
int k = 'A' - line.at(j);// checking that the places needed to go backwards goes less than a in uppercase
line.at(j) = 'Z' - k + 1;
}
}
}
print();
}
void cipher::print() {
if(encoder == true)
cout << "Your encoded string is: " << line << endl;
else
cout << "Your decoded string is: " << line << endl;
}
void cipher::get_shift_key() {
cout << "What integer cipher shift key will you use? (1-20) ";
cin >> shift_key;
}