private void salesFormsToolStripMenuItem_Click(object sender, EventArgs e)
        {   //set the value of transaction type to sales
            transactionType = "Sales";
            frmPurchaseAndSale sales = new frmPurchaseAndSale();

            sales.Show();
        }
        private void purchaseToolStripMenuItem_Click(object sender, EventArgs e)
        {   //set transaction type as purchase in static string
            transactionType = "Purchase";
            frmPurchaseAndSale purchase = new frmPurchaseAndSale();

            purchase.Show();
        }