include <iostream>

using namespace std;

int main () {
    //declaring variables
    double Pi= 3.1416 ;
    double Diameter_ofcircle = 0.0;
    double priceofrailingmaterial = 0.0;
    double Totalpriceofrailingmaterial = 0.0;

    //Getting the user input

    cout<<"Enter the diameter of the circle ";
    cin>>Diameter_ofcircle ;

    cout<<"Enter the price of railing material per foot ";
    cin>> priceofrailingmaterial ;

    Totalpriceofrailingmaterial = ( (Diameter_ofcircle)* Pi ) * ( priceofrailingmaterial) ;

    cout<<"Total price of railing material "<<Totalpriceofrailingmaterial<<endl;

    return 0;
}

This is from codeblocks and I need to transfer this into Visual Studio Express 2010 C++ and this is what I have

#pragma once

namespace Diameter {

    using namespace System;
    using namespace System::ComponentModel;
    using namespace System::Collections;
    using namespace System::Windows::Forms;
    using namespace System::Data;
    using namespace System::Drawing;

    /// <summary>
    /// Summary for Form1
    /// </summary>
    public ref class Form1 : public System::Windows::Forms::Form
    {
    public:
        Form1(void)
        {
            InitializeComponent();
            //
            //TODO: Add the constructor code here
            //
        }

    protected:
        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        ~Form1()
        {
            if (components)
            {
                delete components;
            }
        }
    private: System::Windows::Forms::Label^  lblPi;
    protected: 

    private: System::Windows::Forms::TextBox^  txtPi;
    private: System::Windows::Forms::Label^  lblDiameter;
    protected: 


    private: System::Windows::Forms::TextBox^  txtDiameter;
    private: System::Windows::Forms::Label^  lblPrice;


    private: System::Windows::Forms::TextBox^  txtPrice;
    private: System::Windows::Forms::Label^  lblTotal;


    private: System::Windows::Forms::TextBox^  txtTotal;

    private: System::Windows::Forms::Button^  btnClose;




    private:
        /// <summary>
        /// Required designer variable.
        /// </summary>
        System::ComponentModel::Container ^components;

#pragma region Windows Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        void InitializeComponent(void)
        {
            this->lblPi = (gcnew System::Windows::Forms::Label());
            this->txtPi = (gcnew System::Windows::Forms::TextBox());
            this->lblDiameter = (gcnew System::Windows::Forms::Label());
            this->txtDiameter = (gcnew System::Windows::Forms::TextBox());
            this->lblPrice = (gcnew System::Windows::Forms::Label());
            this->txtPrice = (gcnew System::Windows::Forms::TextBox());
            this->lblTotal = (gcnew System::Windows::Forms::Label());
            this->txtTotal = (gcnew System::Windows::Forms::TextBox());
            this->btnClose = (gcnew System::Windows::Forms::Button());
            this->SuspendLayout();
            // 
            // lblPi
            // 
            this->lblPi->AutoSize = true;
            this->lblPi->Location = System::Drawing::Point(12, 90);
            this->lblPi->Name = L"lblPi";
            this->lblPi->Size = System::Drawing::Size(16, 13);
            this->lblPi->TabIndex = 0;
            this->lblPi->Text = L"Pi";
            // 
            // txtPi
            // 
            this->txtPi->BackColor = System::Drawing::SystemColors::Window;
            this->txtPi->Location = System::Drawing::Point(124, 87);
            this->txtPi->Name = L"txtPi";
            this->txtPi->ReadOnly = true;
            this->txtPi->Size = System::Drawing::Size(75, 20);
            this->txtPi->TabIndex = 1;
            this->txtPi->Text = L"3.1416";
            // 
            // lblDiameter
            // 
            this->lblDiameter->AutoSize = true;
            this->lblDiameter->Location = System::Drawing::Point(12, 32);
            this->lblDiameter->Name = L"lblDiameter";
            this->lblDiameter->Size = System::Drawing::Size(89, 13);
            this->lblDiameter->TabIndex = 2;
            this->lblDiameter->Text = L"Diameter of circle";
            // 
            // txtDiameter
            // 
            this->txtDiameter->Location = System::Drawing::Point(122, 29);
            this->txtDiameter->Name = L"txtDiameter";
            this->txtDiameter->Size = System::Drawing::Size(77, 20);
            this->txtDiameter->TabIndex = 3;
            // 
            // lblPrice
            // 
            this->lblPrice->AutoSize = true;
            this->lblPrice->Location = System::Drawing::Point(12, 160);
            this->lblPrice->Name = L"lblPrice";
            this->lblPrice->Size = System::Drawing::Size(154, 13);
            this->lblPrice->TabIndex = 4;
            this->lblPrice->Text = L"Price of railing material per foot ";
            // 
            // txtPrice
            // 
            this->txtPrice->Location = System::Drawing::Point(194, 215);
            this->txtPrice->Name = L"txtPrice";
            this->txtPrice->Size = System::Drawing::Size(142, 20);
            this->txtPrice->TabIndex = 5;
            // 
            // lblTotal
            // 
            this->lblTotal->AutoSize = true;
            this->lblTotal->Location = System::Drawing::Point(12, 215);
            this->lblTotal->Name = L"lblTotal";
            this->lblTotal->Size = System::Drawing::Size(142, 13);
            this->lblTotal->TabIndex = 6;
            this->lblTotal->Text = L"Total price  of raling material ";
            // 
            // txtTotal
            // 
            this->txtTotal->Location = System::Drawing::Point(194, 160);
            this->txtTotal->Name = L"txtTotal";
            this->txtTotal->Size = System::Drawing::Size(122, 20);
            this->txtTotal->TabIndex = 7;
            // 
            // btnClose
            // 
            this->btnClose->Location = System::Drawing::Point(241, 336);
            this->btnClose->Name = L"btnClose";
            this->btnClose->Size = System::Drawing::Size(75, 23);
            this->btnClose->TabIndex = 8;
            this->btnClose->Text = L"Close";
            this->btnClose->UseVisualStyleBackColor = true;
            this->btnClose->Click += gcnew System::EventHandler(this, &Form1::btnClose_Click);
            // 
            // Form1
            // 
            this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
            this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
            this->ClientSize = System::Drawing::Size(686, 418);
            this->Controls->Add(this->btnClose);
            this->Controls->Add(this->txtTotal);
            this->Controls->Add(this->lblTotal);
            this->Controls->Add(this->txtPrice);
            this->Controls->Add(this->lblPrice);
            this->Controls->Add(this->txtDiameter);
            this->Controls->Add(this->lblDiameter);
            this->Controls->Add(this->txtPi);
            this->Controls->Add(this->lblPi);
            this->Name = L"Form1";
            this->Text = L"Form1";
            this->ResumeLayout(false);
            this->PerformLayout();

        }
#pragma endregion

    private: System::Void btnClose_Click(System::Object^  sender, System::EventArgs^  e) {
                 Application::Exit();
             }
};
}

Diameter of circle is in a label and to enter its number is in a text box.
Pi is in a label and to enter its number is in a text box I have it to read only because its suppose to stay 3.1416.
Price of railing material per foot is in a label and to enter its number is in a text box.
Total price of railing material is in a label and to enter its number is in a text box.

I need to mulitply but I don't know how

This,(Diameter_ofcircle)* Pi * ( priceofrailingmaterial), seems to be ok. what problem are you having with multiplying?

Edited 3 Years Ago by tinstaafl

Add a button "Calculate" to your form.
In the clickhandler Get the text of PI, Price and Diameter out of their respective textboxes.
Convert to float or double, perform a multiplication. Convert this oucome to text and put that text in your total textbox.
Btw. you can use the constant M_PI if you put this in front:

#define _USE_MATH_DEFINES 
#include <cmath>

That way you can delete your PI label and textbox.

Edited 3 Years Ago by ddanbe

Actually that's the only formula you were showing. All your code does is set up the form and its controls.

It appears that converting your string to numbers is the problem not multiplying. One fairly simple way is to use sstream, it the standard extraction operator and can do simple conversions like this

Edited 3 Years Ago by tinstaafl

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