Homework SourseCreate a program in C to encode and decode a message input b
Create a program in C++ to encode and decode a message input by the user.
1. Let the user input a message which will consist of a string or an array of characters.
2. Save the original message in a variable called, original_message.
3. Create a function named encode to encode the message. The function will receive a pointer to the original message and return the string with the encoded message.
4. Create a variable named encoded_message to hold the return value from encode.
5. Create a function named decode to decode the message. The function will receive a pointer to the encoded message and return the string with the decoded message.
6. Create a variable named decoded_message to hold the return value from decode.
7. Test your program with the following strings:
\"Onomatopoeia\", \"Readability\", \"Abstraction & Polymorphism\" \"C++ is the Best!!\"
The output will look like the following, where the first # means the original message and the other two are the encoded and the decoded messages.
Enter a string: #######
Encoded string: #######
Decoded string: #######
Expected output for each of the values required:
\"Onomatopoeia\": encoding: \"Rprodvrrrhld\"
\"Readability\": encoding: \"Thdfddlnlva\"
\"OOP & Polymorphism\": encoding: \"RRR & Rrnaortrjluo\"
\"C++ is the Best!! \": encoding: \"E++ lu vjh Dhuv!! \"
\"2004 !%^&*() ? \": encoding: \"2004 !%^&*() ? \"
Notes: The encoding/decoding will be done the following way:
- Capital and lower case letters will be encoded the same way.
- Consonants input will be shifted two positions. (Ex: b?d, h?j, p?r, x?z, z?b)
- Vowels input will be shifted three positions (Ex: a?d, e?h, i?l, o?r, u?w)
- Numbers and other special characters including blanks will remain untouched.
Solution
Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts. Thanks
Note: The decode method will not work the way you expect it to be. This is because of the encryption technique. More than one character can have same encoded value, for example the char \'O\' is encoded to \'R\' (after shifting 3 places because its a vowel), also char \'P\' is encoded to \'R\' (after shifting 2 places because its a consonent). This makes decoding practically inaccurate. If there is any D,H,l,R or X in the encoded text, the decoded text will have the wrong value
#include<iostream>
using namespace std;
//method to encode a string
string encode(string* message){
string encoded=\"\"; //string to store encoded message
char newchar;
//looping through all characters
for(int i=0;i<message->length();i++){
//getting current character
char c=(*message)[i];
if(c>=\'A\' && c<=\'Z\'){
//upper case character
//checking if it is a vowel
if(c==\'A\' || c==\'E\' || c==\'I\' || c==\'O\' || c==\'U\'){
newchar=c+3; //shifting 3 places
}else{
//consonent, shifting 2 places
newchar=c+2;
}
//wrapping around, if the character go past Z
if(newchar>\'Z\'){
newchar=\'A\'+(newchar-\'Z\');
}
encoded+=newchar;
}else if(c>=\'a\' && c<=\'z\'){
//lower case
//performing similar operations like above
if(c==\'a\' || c==\'e\' || c==\'i\' || c==\'o\' || c==\'u\'){
newchar=c+3;
}else{
newchar=c+2;
}
if(newchar>\'z\'){
newchar=\'a\'+(newchar-\'z\');
}
encoded+=newchar;
}else{
//other character, remaining unchanged
encoded+=c;
}
}
return encoded;
}
//method to decode the message
/*
Please note that this method will not work the way you expect.
This is because of the encryption technique. More than one character
can have same encoded value, for example the char \'O\' is encoded to \'R\'
(after shifting 3 places because its a vowel), also char \'P\' is encoded
to \'R\' (after shifting 2 places because its a consonent). This makes
decoding practically inaccurate. If there is any D,H,l,R or X in the
encoded text, the decoded text will have the wrong value
*/
string decode(string* message){
string decoded=\"\";
char newchar;
for(int i=0;i<message->length();i++){
char c=(*message)[i];
//reversing everything the encode() method did
if(c>=\'A\' && c<=\'Z\'){
if(c==\'D\' || c==\'H\' || c==\'L\' || c==\'R\' || c==\'X\'){
newchar=c-3;
}else{
newchar=c-2;
}
if(newchar<\'A\'){
newchar=\'Z\'-\'A\'-newchar;
}
decoded+=newchar;
}else if(c>=\'a\' && c<=\'z\'){
if(c==\'d\' || c==\'h\' || c==\'l\' || c==\'r\' || c==\'x\'){
newchar=c-3;
}else{
newchar=c-2;
}
if(newchar<\'a\'){
newchar=\'z\'-\'a\'-newchar;
}
decoded+=newchar;
}else{
decoded+=c;
}
}
return decoded;
}
int main(){
string original_message, encoded_message,decoded_message;
//getting input and testing encode,decode methods
cout<<\"Enter a string: \";
getline(cin,original_message);
encoded_message=encode(&original_message);
cout<<\"Encoded string: \"<<encoded_message<<endl;
decoded_message=decode(&encoded_message);
cout<<\"Decoded string: \"<<decoded_message<<endl;
return 0;
}
/*OUTPUT*/
Enter a string: Onomatopoeia
Encoded string: Rprodvrrrhld
Decoded string: Onomatoooeia
