Moj broj

private void button2_Click(object sender, EventArgs e)
        {
            Vreme.Stop();
            if (textBox1.Text == "")
            {
                MessageBox.Show("Niste uneli resenje!", "Moj Broj", MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }
            string temp = textBox1.Text;
            string output = temp.Substring(temp.Length - 1, 1);
            /*if(!(textBox1.Text.Contains(button3.Text)|| textBox1.Text.Contains(button4.Text)|| textBox1.Text.Contains(button5.Text)|| textBox1.Text.Contains(button6.Text)|| textBox1.Text.Contains(button7.Text)|| textBox1.Text.Contains(button8.Text)))
            {
                MessageBox.Show("Neispravan matematicki izraz!", "Moj Broj", MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }*/
            if(textBox1.Text.StartsWith("+")|| textBox1.Text.StartsWith("-")|| textBox1.Text.StartsWith("*")|| textBox1.Text.StartsWith("/"))
            {
                MessageBox.Show("Neispravan matematicki izraz!", "Moj Broj", MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }
            if (output == button3.Text)
            {
                MessageBox.Show("Neispravan matematicki izraz!", "Moj Broj", MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }
            if (output == button4.Text)
            {
                MessageBox.Show("Neispravan matematicki izraz!", "Moj Broj", MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }
            if (output == button5.Text)
            {
                MessageBox.Show("Neispravan matematicki izraz!", "Moj Broj", MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }
            if (output == button6.Text)
            {
                MessageBox.Show("Neispravan matematicki izraz!", "Moj Broj", MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }
            var count = textBox1.Text.Count(x => x == '(');
            var count2 = textBox1.Text.Count(x => x == ')');
            if (count > count2 || count < count2)
            {
                MessageBox.Show("Neispravan matematicki izraz!", "Moj Broj", MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }
            Parser par = new Parser();
            string line = textBox1.Text;

            char[] exp = line.ToCharArray();
            int value = par.EvaluateExpression(exp);

            textBox1.Text = value + "=" + line;

            Resavac re = new Resavac();
            int target;
            int target10;
            int target100;
            int hint1;
            int hint2;
            int hint3;
            int hint4;
            int hint5;
            int hint6;
            tbAnswer.Text = "";
            if (!int.TryParse(label2.Text, out target))
            {
                // tbTarget.Focus();
                return;
            }
            if (!int.TryParse(label3.Text, out target10))
            {
                //tbTarget.Focus();
                return;
            }
            if (!int.TryParse(label4.Text, out target100))
            {
                //tbTarget.Focus();
                return;
            }
            if (!int.TryParse(tbHint1.Text, out hint1))
            {
                tbHint1.Focus();
                return;
            }
            if (!int.TryParse(tbHint2.Text, out hint2))
            {
                tbHint2.Focus();
                return;
            }
            if (!int.TryParse(tbHint3.Text, out hint3))
            {
                tbHint3.Focus();
                return;
            }
            if (!int.TryParse(tbHint4.Text, out hint4))
            {
                tbHint4.Focus();
                return;
            }
            if (!int.TryParse(tbHint5.Text, out hint5))
            {
                tbHint5.Focus();
                return;
            }
            if (!int.TryParse(tbHint6.Text, out hint6))
            {
                tbHint6.Focus();
                return;
            }
            tbAnswer.Text = re.Calculate(target, target10, target100, hint1, hint2, hint3, hint4, hint5, hint6);
        }