Esercizio 22

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Imposta</title>
    </head>
    <body>
        <h1>Calcola la tua imposta</h1>
        <%String cifra = request.getParameter("cifra");
            if (cifra == null) {
                cifra = "";
            }
            String aliquota = request.getParameter("aliquota");
            if (aliquota == null) {
                aliquota = "";
            }
        %>         
        <form action="index.jsp" method="post">
            Inserisci la cifra imponibile <input type="text" value="<%=cifra%>" name="cifra"/><br/>
            Inserisci l'aliquota <input type="text" value="<%=aliquota%>" name="aliquota"/>%<br/>
            <input type="submit" value="invia"/> 
            <input type="reset" value="cancella"/>           
        </form>
        <%
            if ((!cifra.isEmpty()) && (!aliquota.isEmpty())) {
                double c = Double.parseDouble(cifra);
                double a = Double.parseDouble(aliquota);
        %><p> La cifra che devi versare allo stato è di: <%= c * a / 100%> €
            <% }
            %>
        </p>
    </body>
</html>