Question

I’m writing a simple program. There is only one class in it. There is a private member ‘char * number’ and two function (there will be more, but first these should work correctly 🙂 ).

The first one should copy the ‘source’ into ‘number’ variable (and I suppose somewhere here is the problem):

LongNumber::LongNumber(const char * source ){
        int digits = strlen(source);

        char* number = new char[digits+1];
        strcpy( number, source );
        //  cout<<number<<endl; - if the line is uncommented,
        //  the output is correct and there isn't a problem

}

And a print function:

void LongNumber::print(){
    cout<<number<<endl;
    // when I try to print with the same line of code here..it crashes
}

Sure, I’m missing something…but what?

(As this is my first post…do you think the tags are corrected..how would you tagged the post?)

Thank you in advance 🙂

Answer 1

In the LongNumber constructor you declare a new local variable named number and initialize it with a new char array:

char* number = new char[digits+1];

Instead you should leave out the char*, so that it doesn’t look like a new variable declaration and uses the object member variable:

number = new char[digits+1];

With the current code, the member variable number never gets initialized and using it later in print leads to an error.