# Two dimensional array 2: circunference on screen - Practice Exercises Java

## Lesson 4:

## Structures and Strings

## Exercise 4.22:

## Two dimensional array 2: circunference on screen

## Objetive:

## Create a Java program that declares creates a 70x20 two-dimensional array of characters,
"draws" a circumference or radius 8 inside it, and displays it on screen.

Hint: the points in the circumference can be obtained using:

x = xCenter + r * cos angle

y = yCenter + r * sin angle

"sin" and "cos" expect the angle to be measured in radians, instead of degrees.
To convert from one unit to the other, you must remember that 360 degrees = 2 PI
radians (or 180 degrees = PI radians): float radians = (angle * Math.PI / 180.0);

You might draw 72 points (as there are 360 degrees in a circumference, they would
be spaced 5 degreees from each other)

Hint: in Java, cosine is Math.Cos, sine is Math.Sin and PI is Math.PI

## Source Code:

```
public class Main
{
public static void main(String[] args)
{
double r, x, y;
for (int i = 0; i < 360; i += 5)
{
rad = i * Math.PI / 180.0;
x = 35 + 8 * Math.cos(rad);
y = 10 + 8 * Math.sin(rad);
Console.SetCursorPosition((int)x, (int)y);
System.out.print("X");
}
Console.SetCursorPosition(1, 20);
}
}
```

Exercisey 4.22