Caesar Cipher Trouble Keeping letters lowercased and upper cased

[Physiccx]

Please help me correct this code.

3rd post is where the code is at

[kbw]

Can you please use the code format tags to format your code.

In this case, it would help if you posted code that will compile.

[Physiccx]

I'm sorry I didn't know I could do that. Here you go. I touched it up a little bit and got it to compile but I want the data in the files to stay lower cased and upper cased. When I encrypt they go into all caps. When I decrypt, they change to lowercase letters. Here's my new code.

#include <iostream> //For cout and cin etc.
#include <fstream> // To input and output files


class Caesar
{

public: void encrypt(char *inp,char *out,int key);
        void decrypt(char *inp,char *out,int key);
        void readText(char *inp);
};

void Caesar::encrypt(char *inp,char *out,int key) //Function for Encryption
{
        std::ifstream input;
        std::ofstream output;
        char buf;

        input.open(inp); //Reads in the file
        output.open(out); //Gets a new file ready for encryption

        buf = input.get();
        while(!input.eof())
        {
                if(buf >= 'a'&&buf <= 'z') //If it equals a through z
                {
                        buf -= 'a';
                        buf += key;
                        buf %= 26;
                        buf += 'A';
                }
                output.put(buf);
                buf = input.get();
        }

        input.close();
        output.close();
        readText(inp);
        readText(out);
}

void Caesar::decrypt(char *inp,char *out,int key) //Decrypt Function
{
        std::ifstream input;
        std::ofstream output;
        char buf;

        input.open(inp);
        output.open(out);

        buf = input.get();
        while(!input.eof())
        {
                if(buf >= 'A'&&buf <= 'Z')
                {
                        buf -= 'A';
                        buf += 26-key;
                        buf %= 26;
                        buf += 'a';
                }
                output.put(buf);
                buf = input.get();
        }

        input.close();

        output.close();

        readText(inp);
        readText(out);
}

void Caesar::readText(char *inp) //Reading in the text from a files
{
        std::ifstream input;
        char buf;

        input.open(inp);
  std::cout << "\n\n <--- " << inp <<" --->\n";
        buf = input.get();
        while(!input.eof())
        {
                std::cout << buf;
                buf = input.get();
        }
        input.close();
}
int main()
{
 Caesar a;
        int choice,key;
        char inp[30],out[30];
                std::cout << "\n Enter input file: "; //File wanting to be edited
                std::cin >> inp;
                std::cout << "\n Enter output file: "; //New file
                std::cin >> out;
                std::cout << "\n Enter how many places you would like to shift?: "; //How many places the letters are going to move
                std::cin >> key;
        std::cout << "\n\n 1. Encrypt\n 2. Decrypt\n\n Select choice(1 or 2): "; //The choice of encryption or decryption
        std::cin >> choice;

        if(choice == 1)
                a.encrypt(inp,out,key); //Where we call back the void function to use the data from user input
        else if(choice == 2)
                a.decrypt(inp,out,key); //Where we call back the void function to use the data from user input
        else    std::cout << "\n\n Unknown choice"; //If user picks neither 1 or 2

        std::cin.get();

}

<--- Hello.txt --->
hello
turns into
<--- encrypt.txt --->
JGNNQ

how do I keep it lowercased?

Thank you for any response. Any help is appreciated!

[kbw]

That's really complicated. Anyway, the algorithms, do they seem right to you? Do they really implement this? https://en.wikipedia.org/wiki/Caesar_cipher

encrypt:

                if(buf >= 'a'&&buf <= 'z') //If it equals a through z
                {
                        buf -= 'a';
                        buf += key;
                        buf %= 26;
                        buf += 'A';
                }

decrypt:

                if(buf >= 'A'&&buf <= 'Z')
                {
                        buf -= 'A';
                        buf += 26-key;
                        buf %= 26;
                        buf += 'a';
                }