strcpy function with dynamic allocated char array

Question

I am facing problems to make this piece of code work:

char **createCharArray() {
    char **charArray = new char*[PARAM_COUNT];
    for (int i = 0; i < PARAM_COUNT; ++i) {
        charArray[i] = new char[MAXSIZE];
    }
    return charArray;
}
 
void deleteCharArray(char **charArray) {
    for (int i = 0; i < PARAM_COUNT; ++i) {
        delete[] charArray[i];
    }
    delete[] charArray;
}    

int main(){
    char ** test = createCharArray(); 
    char *asd = new char[MAXSIZE];
    cin >> asd;

    for (int i = 0; i < PARAM_COUNT; ++i) {
        strcpy_s(test[i], asd);
    }

    for (int i = 0; i < PARAM_COUNT; ++i) {
        cout << i << " " << test[i] << endl;
    }

    deleteCharArray(test);
    return 0;
}

How do I copy that string into the char array, where am I mistaking?

Edit: As answered by Igor Tandetnik and user17732522 in the comments and Joseph Larson in the reply below, this was solved by adding the buffer argument to the strcpy_s function, making it a total of 3 arguments.

Answer 1

There are a few things I find troublesome. First, you've seen people say you should use std::string instead of char arrays, and that's true. But new programmers should understand the entire language, and so understanding how to use char arrays has value.

So let's ignore C++ strings and look at your code:

char ** test = createCharArray(); // array of pointers to char arrays
char *asd = new char[MAXSIZE];
cin >> asd;

for (int i = 0; i < PARAM_COUNT; ++i) {
    strcpy_s(test[i], asd);
}

for (int i = 0; i < PARAM_COUNT; ++i) {
    cout << i << " " << test[i] << endl;
}

deleteCharArray(test);
return 0;

Let's start with this. We don't know what createCharArray() does. Is it doing everything it should? Not only should it create an array of char pointers, but the way you're using it, it also needs to create the buffers they each point to. So it might look something like this:

char ** createCharArray() {
   char ** array = new char *[PARAM_COUNT];
   for (int index = 0; index < PARAM_COUNT; ++index) {
        array[index] = new char[MAXSIZE];
   }
   return array;
}

If yours looks remarkably different, you may have issues.

After that, let's look at this:

for (int i = 0; i < PARAM_COUNT; ++i) {
    strcpy_s(test[i], asd);
}

As others have said, this version of strcpy_s takes three arguments: strcpy_s(test[i], asd, MAXSIZE);

Note that you're copying the same string into place multiple times. I wonder if your code should really do this:

for (int i = 0; i < PARAM_COUNT; ++i) {
    cin >> asd;
    strcpy_s(test[i], asd, MAXSIZE);
}

And finally, the delete method needs to delete the individual pointers and then the array of pointers.