Hey guys, I was wondering if any of you could help me with some stuff which may seem obvious to you but I'm a beginner.

I'm making a calculator and have reached the part where I am making the buttons change the string on the calculator's "screen".

The way I am doing this is by getting the current line of numbers as a string and then converting the number pressed into a string and then adding the two strings together to form the new calculator display, I then want to display that string.

After reading some books and looking online I thought the best way of doing this would be to use string streaming, so I have made the following:

if(ButtonType == 1) // Numerical buttons processed here
				CurrentInputString = "";
				CurrentInput = 0;
				CurrentInput = ButtonNumber;
				InputOutputStream << CurrentInput;
				InputOutputStream >> CurrentInputString;

				InputOutputStream << TotalInput;
				InputOutputStream >> TotalInputString;

				InputOutputStream << TotalInputString << CurrentInputString;
				//TotalInputString += CurrentInputString;
				InputOutputStream >> TotalInput;
				InputOutputStream << TotalInput;
				InputOutputStream >> TotalInputString;
				this->InputLabel->Text = Convert::ToString(TotalInput);


I had problems setting the text as "TotalInputString" and got these compiler messages:

error C2664: 'void System::Windows::Forms::Control::Text::set(System::String ^)' : cannot convert parameter 1 from 'std::string' to 'System::String ^'
1> No user-defined-conversion operator available, or
1> No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called

Therefore I decided to change it by converting the TotalInput float to a string, which worked but the calculator would only allow me to input 7 numbers before showing "Infinite" on the calculator display and then any further input would result in the first number being a "1" despite pressing any of the buttons.

So my question is - how do I do this? All I want is for the string to allow me to place as many numbers as I need on the display. How do I change the text in such a way?

This was done on Visual C++, sorry if that's a problem.

Thanks in advance to anyone who helps.

7 Years
Discussion Span
Last Post by David_Omid

This is probably not much help...
but it would seem that a possible reason for your problem could be that you have reached the limit of a float. Maybe you could try using a double or a long?
But I am really sure that a float can store much bigger numbers than this.


>cannot convert parameter 1 from 'std::string' to 'System::String ^'
You're mixing standard C++ strings with C++/CLI strings. There's a fundamental difference in that C++/CLI strings are Unicode based while std::string is char based. The least frustrating solution would be to pick one and stick with it, but you can also convert between the two:

this->InputLabel->Text = gcnew System::String(TotalInput.c_str());

Thanks for the help from both of you, I am going to see what I can do now.

Narue, do you mean that I am trying to mix up two different string classes and should just pick one? Which one would you suggest using, or are they both pretty much the same? The problem I see is that I may have to convert it at certain points.


I just tried the conversion that Narue suggested and it hasn't worked. I am still getting strange numbers coming up.

Edited by David_Omid: n/a


Any more nuggets of wisdom out there?

Edited by David_Omid: n/a


I am still having problems, if there is anyone else out there that can provide any assistance whatsoever, it would be greatly appreciated.


Sorry, but what else am I supposed to do? The last person who posted other than me did so 11 hours ago.

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