How to covert Textbox to integer array in c++/cli

Question

I'm trying to convert the textbox to an integer array assuming that every character of the textbox is a digit.

//textbox is named input
int size = this->input->Text->Length;
int * num = new int[size];
int Counter = 0;

//for loop used since textbox inputs like a calculator
//Ex: the number: 234 is inputed: 2, then 23, then 234
for (int i = size; i > 0; i--)
{
    num2[Counter] = System::Convert::ToInt32(input->Text[i-1]);
    Counter += 1;
}

Array of numbers should be:

num[0] = 4, num[1] = 3, num[2] = 2

Upon research though it seems that it's finding the integer unicode value instead.

You need to iterate over the textbox characters, presumably via input->Text[i]. But i should go from size-1 to 0. — Malcolm McLean, May 22 '17 at 23:19
@MalcolmMcLean: Best not, or your loop will run forever. OP is doing it right, if we ignore the fact that it doesn't matter because `i` is never used. — Lightness Races in Orbit, May 23 '17 at 00:00
To @sergiol: one would generally use C++/CLI *or* Managed C++. These are different iterations of C++ with .Net Interop, and Managed C++ is only in Visual Studio 2005. — crashmstr, May 23 '17 at 12:01
@crashmstr: I upvoted you for clarifying me. I never knew what was the difference between Managed C++ and C++/CLI ! — sergiol, May 23 '17 at 13:27
Possible duplicate of [How to convert char to int?](https://stackoverflow.com/questions/3665757/how-to-convert-char-to-int) — crashmstr, May 23 '17 at 14:42
You are using a method that gets you the integer unicode value, not the numerical value of the digit: [Convert.ToInt32 Method (Char)](https://msdn.microsoft.com/en-us/library/ww9t2871(v=vs.110).aspx) (linked duplicate shows how to do this) — crashmstr, May 23 '17 at 14:43

Alexander Petrov · Accepted Answer · 2017-05-23T14:28:56.040

Code input->Text[i-1] returns a single Unicode character value of the wchar_t type. That is implicitly cast to Int32, i.e. the symbol code.

You have to convert the char to a string, before converting to the number. You can use the Substring method or the ToString method for this purpose.

You can do it as follows:

String^ text = this->input->Text;
int size = text->Length;
int * num = new int[size];

for (int i = size - 1; i >= 0; i--) {
    num[i] = Convert::ToInt32(text->Substring(size - i - 1, 1));
}

However, you should not mix managed and unmanaged code.

There is a better way. Use a generic collection instead of an array.

String^ text = this->input->Text;
int size = text->Length;
List<int>^ nums = gcnew List<int>();

for (int i = size - 1; i >= 0; i--) {
    nums->Add(Convert::ToInt32(text[i].ToString()));
}

Don't forget

using namespace System::Collections::Generic;

The list can be accessed by index like an array:

nums[i]

So it is convenient to work with. And most importantly, do not need to worry about freeing memory.

You've posted code. How about adding an explanation of what this code does and how it answers the question to make this a better answer? — crashmstr, May 23 '17 at 14:09
@crashmstr - I'm not native english speaker, so it's hard for me to write in English. I do it slowly, tormenting translator. So easy to write the code, so hard to write in English. — Alexander Petrov, May 23 '17 at 14:34

How to covert Textbox to integer array in c++/cli

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