Weird issue with ascii codes

[Aalnius]

Hi guys,

so im having a weird issue when im running my cypher program when it shifts the alphabet it adds a random char to the end which im guessing is because there isn't a null terminator at the end of the cypherbet array.
http://i47.tinypic.com/152kwfd.jpg
so i was wondering if anyone could help me out and point out if that is indeed the reason why its happening and how i could add a terminator to the end of the array.

i've tried cypherBet[27] = '/0'; but apparently that corrupts the array.
so im a little stuck.

code below:

char* makeCypher(int shiftVal)
{
	
	char alphabet[27] = {97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108,
							109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, '/0'};
	char cypherBet[27];
	int loopNum;
	cout << "The plain text alphabet is: \n";
	for(int g = 0; g < 26; g++)
	{
		cout << alphabet[g];
	}
	cout << endl;
	cout << "This is the Cypertext alphabet: \n";
	for(int h = 0; h < alphabet[h] && alphabet[h] != '/0'; h++)
	{
		if((alphabet[h] +shiftVal) > 122)
		{
			loopNum = ((alphabet[h]+shiftVal)-122);
			cypherBet[h] = alphabet[loopNum-1];
		}
		else
		{
			cypherBet[h] = alphabet[h] + shiftVal;
		}
		cout << cypherBet[h];
	}
	cout<<endl;
	return cypherBet;
}

thanks in advance guys.
Alan

[Peter87]

You have to use the backslash when writing the null character '\0'.

What exactly is it that you are trying to test with h < alphabet[h]? I don't think it should be there.

cypherBet is a local variable and will no longer exist when the function returns. It's not a good idea to return a pointer to it because any attempt to read the array outside the function would be an error because the array does no longer exists.

[Aalnius]

ahh okay thanks, the reason h < alphabet[h] is there is because i kept getting access violation errors without it for some reason and that seemed to fix it without causing other problems.

i havn't set up the return bit properly yet i just needed it to return something whilst i finished the rest of the function


edit : i changed the direction of the slash but it still corrupts and ive changed my function so its void and doesn't return anything, but it still happens.

[Chervil]

Did you change both places where you had '/0' to '\0'?
If you define alphabet like this, the compiler will add the null terminator, so that takes care of one issue.

    char alphabet[27] = "abcdefghijklmnopqrstuvwxyz";

If you code the for loop like this, it takes care of the other one:

        for (int h=0; alphabet[h]; h++)

[Aalnius]

yeh i changed both, but its the cypherbet array thats getting corrupted when i try that

[Chervil]

void makeCypher(int shiftVal)
{

	char alphabet[27] = "abcdefghijklmnopqrstuvwxyz";
	char cypherBet[27];

    const char z = 'z';

	int loopNum;
	cout << "The plain text alphabet is: \n";
	for(int g = 0; g < 26; g++)
	{
		cout << alphabet[g];
	}
	cout << endl;
	cout << "This is the Cypertext alphabet: \n";
	for (int h=0; alphabet[h]; h++)
	{
		if((alphabet[h] +shiftVal) > z)
		{
			loopNum = ((alphabet[h]+shiftVal)-z);
			cypherBet[h] = alphabet[loopNum-1];
		}
		else
		{
			cypherBet[h] = alphabet[h] + shiftVal;
		}
		cout << cypherBet[h];
	}
	cout<<endl;

}

[Aalnius]

that works perfectly thanks alot now to make sure i fully understand what went wrong before i carry on with the rest of my program