Thread: Encryption Algorithm...

Okay, I haven't done this programming thing in a long while, so I'm coming back to it slowly...

I'm writing an extremely simple word encryption program, that'll I'll improve later, add decryption and more complex algorithms and such, but first I need to debug it. What it's supposed to do is take the word and add one to each letter(ie. abc would become bcd). For some reason, though, which I can't come up with, it just outputs garbage...

Here's the program:

Code:

#include <iostream>
#include <cstdlib>

char collect(void);
char encrypt(char word[40]);

int main()
{
  char output[40];
  output[40] = collect();
  output[40] = encrypt(output);
  std :: cout << "Your encryption of the word is " << output << ".\n";
  std :: system("pause");
  return (0);
}
  
char collect(void)
{
  char word[40];
  std::cout << "Input your word.\n";
  std::cin >> word;
  return (word[40]);
}

char encrypt(char word[40])
{
  int index;
  for(index = 0; index <= 40; index++)
  {
    word[index]++;
    if(!word[index])
    {
      break;
    }
  }
  return (word[40]);
}

It's pretty self-explanatory, but in case you guys don't get it, which is unlikely, the function char encrypt(char word[40]) at the end of the program adds one to each letter, and then it checks if there is data in the following array entries. If not, it breaks from the loop and returns the encrypted word. I must have done something wrong, though, and I wondered if you guys would mind helping me out on this one.

Thanks in advance!(Don't worry. I'll be sure to thank you afterward, also :P)

tech your changes wont let it compile.

Okay, thanks.

You think you are passing arrays around but you aren't.

Lets make this a little easier by using std::string

Code:

#include <iostream>
#include <string>
#include <cstdlib>

std::string collect(void);
std::string encrypt(std::string &);

int main()
{
  std::string output = collect();
  output = encrypt(output);
  std :: cout << "Your encryption of the word is " << output << ".\n";
  std::cin.ignore();
  return 0;
}
  
std::string collect(void)
{
  std::string word;
  std::cout << "Input your word.\n";
  std::cin >> word;
  return word;
}

std::string encrypt(std::string& word)
{
  int index;
  for(index = 0; index <= word.length(); index++)
    word[index]++;
  return word;
}

The Brain please show me one string literal in my program tht isn't a prompt.
In fact std::string is the better option. Here is why.
A null terminated array of characters (aka c-string) stores the characters in contigious memory.
A std::string may use array segments, meaning that the entire string may not be stored in the same contigious block of memory.

Since when does the string class use string literals?

Originally Posted by techrolla

Here it is with c strings, this works for me, and it gets rid of returning local variables, etc.

Code:

void collect(char *str)
{
  std::cout << "Input your word.\n";
  std::cin >> str;
}

Please shut up now. This is your third post of crap in this thread.

What happens if I input more then 40 characters?

Sean ^

It doesnt.

Originally Posted by RoD

It doesnt.

I know that... I wasn't asking the question for educational gain.


Hey The Brain - No.