Recursion - Building Java Programs: A Back to Basics Approach - page 727

We know that at this point, the computer stops executing main and turns its atten-
tion to the drawTriangle method. This step is analogous to picking up the piece of
paper with drawTriangle written on it and placing it over the piece of paper with
main on it:

public static void main(String[] args) {

drawTriangle();

public static void drawTriangle() {
System.out.println(" *");
System.out.println(" ***");
System.out.println("*****");
System.out.println();
}

drawTwoTriangles();

}

Now we execute each of the statements in drawTriangle from first to last, then
go back to main , removing the drawTriangle sheet. When we go back to main we
will have finished the call on drawTriangle , so the next step is the call on
drawTwoTriangles :

public static void main(String[] args) {
drawTriangle();
drawTwoTriangles();
}

So we grab the piece of paper with drawTwoTriangles on it and place it over the
paper with main on it:

public static void main(String[] args) {

drawTriangle();

public static void drawTwoTriangles() {
drawTriangle();
drawTriangle();
}

drawTwoTriangles();

}

The first thing to do here is the first call on drawTriangle:

public static void main(String[] args) {

drawTriangle();

public static void drawTwoTriangles() {
drawTriangle();
drawTriangle();
}

drawTwoTriangles();

}