# Exercise 1

```java 
class Param1
{
	public int y;
	// default constructor here
	public void method1(int x)
	{
		y = 2*x;
	}
	
	public int getY()
	{
		return y;
	}
}
```

Param1 q1 = new Param1();
int y = 25; //Local Variable
q1.y = 100; //Field Variable
q1.method1(y); //method1(25) -> this.y = 50
System.out.println(y);
System.out.println(q1.getY());

` y = 25 `
` this.y = 50 `

```java
class Param2
{
	public int y;
	// default constructor here
	public void method1(int x)
	{
		y = 2*x;
	}
	
	public int method2(int w)
	{
		return 3*w;
	}
}
```

Param2 q2 = new Param2();
int y = 25; //Local Variable
q2.y = 100; //Field Variable
q2.method1(y); //method1(25) -> this.y = 50
System.out.println(y);
System.out.println(q2.y);
System.out.println(q2.method2(y));

`y = 25`
`this.y = 50`
`method2(y) = 3*y = 3*25 = 75`

```java
class Param3
{
	public int y;
	// default constructor here
	public void method1(int y)
	{
		y = y*3; // Local Variable
	}
	public int getY()
	{
		return y;
	}
}
```

Param3 q3 = new Param3();
q3.y = 100; //Field Variable
q3.method1(25); //Local y = 25x3 = 75
System.out.println(q3.getY());

`y = 100`

```java
class Param4
{
	private int w;
	public Param4()
	{
		w = 5;
	}
	public void method1(int w)
	{
		this.w = w*3;
	}
	public int getW()
	{
		return w;
	}
}
```

Param4 q4 = new Param4();
System.out.println(q4.getW());
q4.method1(25);
System.out.println(q4.getW())

` w = 5 `
` this.w = 15 `
` w = 15 `

# Exercise 2

```java
class Param5
{
	private int a, b;
	public Param5()
	{
		b = 2;
	}
	public void method1(int b)
	{
		a = this.b + 5;
		System.out.println(a);
		a = method2(b);
		System.out.println(a);
		System.out.println(this.b);
	}
	public int method2(int a)
	{
		b = 2 + a;
		return this.a + b;
	}
}
```

Param5 q5 = new Param5();
q5.method1(3);

Field Variable b = 2
Local Variable b = 3
Field a = 2 + 5 = 7
output 7
a = method2(3)
	Field b = 2 + 3  = 5
	return 7 + 5 = 12
Field a = 12
output 12
output 5

```java
public void arrayMethod(int[] stats) //B
{
	for (int k = 0; k < stats.length; k+=2)
		stats[k] = k; //C
}
```

int [] numbers = {5, 10, 15, 20}; //A
arrayMethod(numbers);

Draw four state-of-memory diagrams to indicate the situation immediately after A has been executed, on starting execution of the method at B, immediately before returning from the method i.e. at C and after the method has been fully executed i.e. in the order in which the statements above are executed.

| numbers | -> | 5, 10, 15, 20 |
| numbers | -> | stats |
| stats | -> | 0, 10, 2, 20 |
| numbers | -> | 0, 10, 2, 20 |