# Pre-Lab Assignment: Lab #2

1. What is the difference between a variable and a constant?

2. Explain what each of the lines below does. Be sure to indicate how each is different from the others.
1. int x;

2. int x = 3;

3. x = 3;

3. The following program reads three integers and prints the average. Fill in the blanks so that it will work correctly.
```
// **********************************************
// FILE: Average.java
// Author: Adrienne Bloss
//
// Purpose: Read three integers from the user and print their average
// **********************************************

import cs1.Keyboard;
public class Average
{
public static void main(String[] args)
{
int val1, val2, val3;
double average;

// get three values from user
System.out.println("Please enter three integers and " +
"I will compute their average");

____________________________________

____________________________________

____________________________________

//compute the average

____________________________________

//print the average

____________________________________

}

}
```

4. Given the declarations below, find the result of each expression.
```int a = 3, b = 10, c = 7;
double w = 12.9, y = 3.2;

a + b * c

a - b - c

a / b

b / a

a - b / c

w / y

y / w

a + w / b

a % b / y

b % a

w %  y

```