Vežba 06, Zadatak 2

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

namespace Vezba_06_2017_Zadatak2
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string s1 = textBox1.Text;
            string s2 = textBox2.Text;

            textBox3.Text = s1.Length.ToString();
            textBox4.Text = s1 + s2;
            textBox5.Text = s1.ToUpper();
            textBox6.Text = s1.ToLower();

            textBox9.Text = s1.IndexOf(textBox7.Text).ToString();
            textBox10.Text = s1.LastIndexOf(textBox8.Text).ToString();

            textBox11.Text = s1.Substring((int)(numericUpDown1.Value), (int)(numericUpDown3.Value)).ToString();
            textBox12.Text = s1.Remove((int)(numericUpDown2.Value), (int)(numericUpDown4.Value)).ToString();
            textBox13.Text = s1.Replace(textBox14.Text, textBox15.Text);
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Close();
        }
    }