Question

Programming Requirements

You will write a program consisting of the following files:

1. cipher.cpp: Contains your main function, provides all input/output with the user, and is responsible for reading the file into a buffer (i.e., a string).
2. encrypt.cpp: Contains a function named encrypt, that takes two parameters: (i) a string containing text to encrypt, and an integer for the shift value. The function should declare a string, store the encrypted text in it, and return the string.
3. decrypt.cpp: Contains a function named decrypt, that takes two parameters: (i) a string containing text to decrypt, and an integer for the shift value. The function should create a string variable, store the decrypted text in it, and return the string.
4. encrypt.h: Contains the function header for the encrypt function. Do not forget your header guard! This file should be included by cipher.cpp.
5. decrypt.h: Contains the function header for the decrypt function. Do not forget your header guard! This file should be included by cipher.cpp.

Your program should do the following:

1. Ask the user if they want to encrypt or decrypt some text.
2. Ask the user for the shift value.
3. Ask the user for the file they wish to encrypt/decrypt.
4. Perform the encryption or decryption of the file based on the user's input in 1.
5. Print the string returned from your encrypt/decrypt function.

Here are some examples of the full run of the program:

Sample Run 1 (sample1-enc.txt)

ranger0$ ./cipher

Would you like to (e)ncrypt or (d)ecrypt a file? e

Enter the shift value: 8

Enter the path to the file: sample1-enc.txt

The encrypted text is:

Twzmu qxacu lwtwz aqb iumb, kwvamkbmbcz ilqxqakqvo mtqb, aml lw mqcauwl bmuxwz qvkqlqlcvb cb tijwzm mb lwtwzm uiovi itqyci. Cb mvqu il uqvqu dmvqiu, ycqa vwabzcl mfmzkqbibqwv cttiukw tijwzqa vqaq cb itqycqx mf mi kwuuwlw kwvamycib. Lcqa icbm qzczm lwtwz qv zmxzmpmvlmzqb qv dwtcxbibm dmtqb maam kqttcu lwtwzm mc ncoqib vctti xizqibcz. Mfkmxbmcz aqvb wkkimkib kcxqlibib vwv xzwqlmvb, acvb qv kctxi ycq wnnqkqi lmamzcvb uwttqb ivqu ql mab tijwzcu.

Sample Run 2 (sample1-dec.txt)

ranger0$ ./cipher

Would you like to (e)ncrypt or (d)ecrypt a file? d

Enter the shift value: 12

Enter the path to the file: sample1-dec.txt

The decrypted text is:

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Answer 1

N.B: For Decryption I have subtract the shift value, but you can add it also. I have supply decrypted file name which is created from of encrypted text for demo purpose. You can also modify the program according to your requirement.

Compile method

Create all files indivisually first than compile

c++ cipher.cpp encrypt.cpp decrypt.cpp -o cipher

Run

./cipher

Code

cypher.cpp

#include<iostream>
#include<fstream>
#include <string>
#include "encrypt.h"
#include "decrypt.h"
using namespace std;
int main()
{
char ch;
int shift_val;
string word,fname,ret_s1;
  
ifstream file; //File Pointer for reading

cout<<"Would you like to (e)ncrypt or (d)ecrypt a file?";
cin>>ch;
cout<<"Enter the shift value:";
cin>>shift_val;
cout<<"Enter the path to the file:";
cin>>fname;
file.open(fname); //Open the file in Read Mode
if(ch=='e')
{
cout<<"The Encrypted text:"<<endl;
while(file >> word) // To get you all the lines.
{
ret_s1.resize(word.size());//initilize string
ret_s1=encrypt(word, shift_val);
cout<<ret_s1<<" "; // Prints Encrypted text.
}
cout<<endl;
file.close(); //Close the file
}

if(ch=='d')
{
cout<<"The Decrypted text:"<<endl;
while(file >> word) // To get you all the lines.
{
ret_s1.resize(word.size());
ret_s1=decrypt(word, shift_val);
cout<<ret_s1<<" "; // Prints decrypted text.
}
cout<<endl;
file.close(); //Close the file
}

return 0;
}

encrypt.cpp

#include "encrypt.h"
string encrypt(string s1, int shift_val)
{
string ret_s;
ret_s.resize(s1.size());
int i;
for (i = 0; i < s1.size(); i++)
{
ret_s[i]=s1[i]+shift_val;
}
ret_s[i++]='\0';
return ret_s;
}

decrypt.cpp

#include "decrypt.h"
string decrypt(string s1, int shift_val)
{
string ret_s;
ret_s.resize(s1.size());
int i;
for (i = 0; i < s1.size(); i++)
{
ret_s[i]=s1[i]-shift_val;
}
ret_s[i++]='\0';
return ret_s;
}

encrypt.h

#include <string>
using namespace std;
string encrypt(string s1, int shift_val);

decrypt.h

#include <string>
using namespace std;
string decrypt(string s1, int shift_val);

Screen Shots

iteradmin@C126-C072: - File Edit View Search Terminal Help iteradmin@c126-C072:~$ c++ cipher.cpp encrypt.cpp decrypt.CPP iteradmin@c126-C072:~$ C++ cipher.cpp encrypt.cpp decrypt.cpp -o cipher iteradmin@c126-C072:-$ ./cipher Would you like to (encrypt or decrypt a file?e Enter the shift value: 1 Enter the path to the file: source.txt The Encrypted text: Qsblbti Diboesb cipj JUFS- CCTS iteradmin@c126-C072:~$ ./cipher Would you like to (encrypt or (d)ecrypt a file?d Enter the shift value:1 Enter the path to the file:decrypt.txt The Decrypted text: Prakash Chandra Bhoi ITER, BBSR iteradmin@c126-C072:~$ .

#include<iostream> #include<fstream> #include <string> #include "encrypt.h" #include "decrypt.h" using namespace std; int main() char ch; int shift_val; string word, fname, ret_51; ifstream file; //File Pointer for reading cout<<"Would you like to (e)ncrypt or (d)ecrypt a file?"; cin>>ch; cout<<"Enter the shift value:"; cin>>shift_val; cout<<"Enter the path to the file:"; cin>>fname; file.open(fname); //Open the file in Read Mode if(ch=='e') cout<<"The Encrypted text:"<<endl; while(file >> word) // To get you all the lines. ret_s1.resize(word.size());//initilize string ret_s1=encrypt(word, shift_val); cout<<ret_$1<<" "; // Prints Encrypted text. cout<<endl; file.close(); //Close the file

if(ch=='') cout<<"The Decrypted text:"<<endl; while(file >> word) // To get you all the lines. ret_s1.resize(word.size(); ret_s1=decrypt(word, shift_val); cout<<ret_s1<<" "; // Prints decrypted text. cout<<endl; file.close(); //Close the file return 0; C++