Programacion

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace Divisor_de_Tension_01
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

double vi, r1, r2;
        int a = 0;
        int b = 0;
        int c = 0;
        double Vout;
        double[] multiplos = { 0.000001, 0.001, 1, 1000, 1000000 };
        string cadena;

private void Form1_Load(object sender, EventArgs e)
        {
            cmbTension.SelectedIndex = 2;
            cmbR1.SelectedIndex = 1;
            cmbR2.SelectedIndex = 1;
        }

private void calcular()
        {
            vi = vi * multiplos[a];
            r1 = r1 * multiplos[b + 2];
            r2 = r2 * multiplos[c + 2];

Vout = ((vi * r2) / (r1 + r2));

lblTension.Text = prefijo(vi, 1) + "V";
            lblVo.Text = prefijo(Vout, 3) + "V";
            lblR1.Text = prefijo(r1, 1) + "Ω";
            lblR2.Text = prefijo(r2, 1) + "Ω";
        }

private string prefijo(double numero, int decimales)
        {
            if (numero >= 1000000)
            {
                numero = numero / 1000000;
                cadena = Math.Round(numero, decimales) + "M";
            }
            else
            {
                if (numero >= 1000)
                {
                    numero = numero / 1000;
                    cadena = Math.Round(numero, decimales) + "K";
                }
                else
                {
                    if (numero >= 1)
                    {
                        numero = Math.Round(numero, decimales);
                        cadena = numero.ToString();
                    }
                    else
                    {
                        if (numero >= 0.001)
                        {
                            numero = numero * 1000;
                            cadena = Math.Round(numero, decimales) + "m";
                        }
                        else
                        {
                            numero = numero * 1000000;
                            cadena = Math.Round(numero, decimales) + "u";
                        }
                    }
                }
            }
            return (cadena);
        }

private void cmbTension_SelectedIndexChanged(object sender, EventArgs e)
        {
            a = cmbTension.SelectedIndex;
        }

private void cmbR1_SelectedIndexChanged(object sender, EventArgs e)
        {
            b = cmbR1.SelectedIndex;
        }

private void cmbR2_SelectedIndexChanged(object sender, EventArgs e)
        {
            c = cmbR2.SelectedIndex;
        }

private void btnCalcular_Click(object sender, EventArgs e)
        {
            vi = Convert.ToDouble(txtTension.Text);
            r1 = Convert.ToDouble(txtR1.Text);
            r2 = Convert.ToDouble(txtR2.Text);
            calcular();
            lblSalida.Text = "Vout = " + lblVo.Text;
        }
    }
}

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