How to look content of dynamic string array in c++ in VS debugger

Question

What is wrong in this code? I want to make a dynamic string array using string*, not collections, vectors, etc.

    int abc = 4;
string* abcdef = new string[abc];
for (int i = 0; i < abc; i++)
{
    cin >> abcdef[i];
}

It doesnot give any error but the data I enter is not appearing in locals box in VS2012.

Regards

Did you try adding a print (`cout <<`) loop to see what is stored in `abcdef`? — Fred Foo, Aug 23 '13 at 13:31
It depends on your input data. Also, what is wrong with `std::vector` btw? — Nawaz, Aug 23 '13 at 13:32
Yes I added cout << in loop and the data is outputting, but why it donot appears in local box when debugging. Only string at 0 index appears in the locals box. — , Aug 23 '13 at 13:42
I guess I should have been more specific in my question: Did you do what biocomp recommended below (that is what I meant by "expand the array")? — Zac Howland, Aug 23 '13 at 13:53
Yes writing "abcdef, 4" in watch block worked, as biocomp said. — , Aug 27 '13 at 15:09

score 3 · Answer 1 · answered Aug 23 '13 at 13:44

3

This works just fine:

#include <iostream>
#include <string>

int main()
{
    int count = 4;
    std::string* stringArray = new std::string[count];
    for (int i = 0; i < count; i++)
    {
        std::cin >> stringArray[i];
    }

    for (int i = 0; i < count; i++)
    {
        std::cout << "stringArray[" << i << "] = " << stringArray[i] << std::endl;
    }

    delete [] stringArray;
    return 0;
}

Though, the better solution would still be:

int main()
{
    std::vector<std::string> stringVector;
    std::cout << "Enter Strings (Ctrl-Z to finish):" << std::endl;
    std::copy(std::istream_iterator<std::string>(std::cin), std::istream_iterator<std::string>(), std::back_inserter<std::vector<std::string>>(stringVector));
    std::copy(stringVector.begin(), stringVector.end(), std::ostream_iterator<std::string>(std::cout, "\n"));
    return 0;
}

answered Aug 23 '13 at 13:44

Zac Howland

15,777
1
26
42

Too much of `std::`, why not `using namespace std;`? – thefourtheye Aug 23 '13 at 13:53
Unless we have C++11 supported compiler, it would fail with `std::back_inserter>` – thefourtheye Aug 23 '13 at 14:02
1

It avoids potential naming conflicts, especially when displaying code for someone else to use and not knowing what compiler they are using, which libraries they are including, etc. I rarely use `using namespace [fill in the blank];` See http://stackoverflow.com/questions/1452721/why-is-using-namespace-std-considered-bad-practice and http://stackoverflow.com/questions/1265039/using-std-namespace – Zac Howland Aug 23 '13 at 14:02
@thefourtheye: There is nothing wrong with `std::back_inserter>` in any version of C++. The only change you would have to make in older versions is to separate the ">>" so the compiler does not try to treat it like an operator. But that changes it to `std::back_inserter >`. The caveat to that: `std::istream` did not properly support insertion and extraction of `std::strings` in most compilers prior to the new standard. – Zac Howland Aug 23 '13 at 14:04
@ZacHowland Yes. That's exactly what I meant :) – thefourtheye Aug 23 '13 at 14:05

score 3 · Accepted Answer · answered Aug 23 '13 at 13:50

Oh, looks like your question is about VS debugger.

That's how VS debugger shows contents of a pointer. It doesn't know it's an array, so it just shows you what it points to - the first element. To show all of them in watch window type "abcdef, 4" (where 4 is size of an array, obviously).

How to look content of dynamic string array in c++ in VS debugger

2 Answers2