Constrain libary and code help

Im using the keypad libary to monitor the pushbuttions on my Joystick.

I used the Constrain libary to limit the pushbutton count from 0 to 3 because I want 4 Lcd menus screens.

But when I try to reference the menu in the constrain string i get and error

#include <Keypad.h>
#include <LiquidCrystal.h>
#include <Constrain.h>

Constrained menu( 2 , 0 , 3 );

const byte ROWS = 4; //four rows
const byte COLS = 2; //three columns
char keys[ROWS][COLS] = {
{'1','2'},
{'3','4'},
{'5','6'},
{'7','8'}
};
byte rowPins[ROWS] = {48, 46 , 44, 42}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {52, 50}; //connect to the column pinouts of the keypad

Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(2, 3, 4, 5, 6, 7);

int photoIn = 0; // photoresistor on Analogue Pin 1
int ledOut = 12; // LED on Digital Pin 7
int aiValue = 0; // input value
int setPoint = 10;

void setup() {
Serial.begin(9600);
menu = 0;
lcd.begin(16, 2);
lcd.print(" Umbrella Corp");
lcd.setCursor(0, 1);

delay(3000);
}

void loop() {
char key = keypad.getKey();
switch (key){

case '1':
menu++;
break;

case '5':
menu--;
break;

}

Serial.println(menu.value,DEC);
delay (100);
}

I used the Constrain libary

First I've heard of it. Got a link?

But when I try to reference the menu in the constrain string i get and error

What error?

http://www.arduino.cc/playground/Code/Constrain

Your code compiles here.

I explained that wrong.

The Constrain works as the menu ++ and menu-- count up and down.

what i want to do is this. i have 4 menu screens i want to switch to from the push buttions on my joystick ( menu++ and menu--)

but if i do try this

switch (menu){

case 1:

//change screens

break:

case 2:

//change to next screen

break:

it errors out

Im sure ther is a better way to do what i want

but in a nubee

thanks john

but if i do try this...it errors out

What is "it"? What does "it errors out" mean?

Is the code compiling but not behaving correctly? If so, what is it actually doing? What are you expecting it to do?

Or, is the code failing to compile? If so, show your actual code, and the error message(s) that you are seeing.