custom string exercise in c++

Question

I have a custom string class that uses an array of chars,

class MyString
{

private:
int length; 
char *chars; 

public:
MyString(const char* input)
{
    length = 0; 
    while (input[length] != '\0')
        ++length;

    chars = new char[length + 1];

    for (int j = 0; j < length; j++)
        chars[j] = input[j];
}

However when I use this class with a simple output I am getting a strange result in the console:

MyString newStr = "Test";
cout << newStr;

Gives me this output in the console:

Test═²²²²½½½½½½½½■ε■ε■ε■

This is with Visual Studio 2010 Win32 console app. I don't really know c++ very well and this is my first try at it.

You haven't shown the code that outputs the string. Show that. — Cheers and hth. - Alf
– Cheers and hth. - Alf, Commented Jan 18, 2011 at 2:34

Hilydrow · Accepted Answer · 2011-01-18 02:22:08Z

2

You forgot to put \0 at the end of chars[]. \0 is the character that MUST be put at the end of a char sequence. Otherwise, your program will output some random stuff (the bits after your array in memory) until it finds a \0.

answered Jan 18, 2011 at 2:22

Hilydrow

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Comments

Daniel Gallagher · Accepted Answer · 2011-01-18 02:24:09Z

2

Your loop that copies input to chars isn't including the NUL terminator. Change the loop condition to j <= length and it should work.

answered Jan 18, 2011 at 2:24

Daniel Gallagher

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Comments

David Weiser · Accepted Answer · 2011-01-18 02:23:51Z

1

There are a couple of things that I'd recommend:

You are not null terminating your chars[]
you need to overload the << operator. Go to: http://www.fredosaurus.com/notes-cpp/oop-friends/overload-io.html for an example.

answered Jan 18, 2011 at 2:23

David Weiser

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