1. Derived from Building Java Programs by Stuart Reges & Marty Stepp
Nested for Loops
Derived from Building Java Programs by Stuart Reges & Marty Stepp

2. Example output to produce: hourglass
|\ /| | \ / |
| \/ |
| /\ |
| / \ |
|/ \|

3. Hourglass: Decomposition
|\ /| | \ / |
| \/ |
| /\ |
| / \ |
|/ \|

4. Hourglass: Pseudocode
draw line |\ /| | \ / | draw top half
| \/ |
| /\ |
| / \ | draw bottom half
|/ \|
draw line

5. Hourglass: Pseudo Code
Draw a solid line
Draw the top half of the hourglass
Draw the bottom half of the hourglass

6. main( ) looks like public class DrawFigure {
public static void main (String [] args) {
drawLine();
drawTop ();
drawBottom ();
drawLine (); }
public static void drawLine () {
code
SOLVE EACH METHOD INDEPENDENTLY

7. Solve for the solid line
Write a + on the output line
Write 6 – on the output line
Go to a new output line
public static void drawLine( ) {
System.out.print ("+");
for (int i=1; i <= 6; i++) {
System.out.print (“-”); }
System.out.println (“+”);
Translated into a static method

8. Solve for Top Half of Hourglass
for (each of 3 lines) {
write a bar on the output line.
write some spaces on the output line.
write a backslash on the output line.
write a slash on the output line.
go to a new line of output. }
To help you… create a table to determine the output of spaces

9. Table for Top Half of hourglass
Line
Spaces 1 4 2 3

10. Refining pseudocode for Top Half of Hourglass
for (line going from 1 to 3) {
write a bar on the output line.
write (line – 1) spaces on the output line.
write a backslash on the output line.
write (6 - 2 * line) spaces on the output line.
write a slash on the output line.
go to a new line of output. }

11. drawTop () // produces the top half of the hourglass figure
public class drawTop {
for (int line = 1; line <= 3; line++) { System.out.print (“|”);
for (int i = 1; i <= (line-1); i++) {
system.out.print(“ “); }
System.out.print (“\\”);
for (int i = 1; i <= (6-2*line); i++) { system.out.print(“ “);
System.out.print (“/”);
System.out.print (“|”);

12. Using a Class Constant // refers to height of two halves
public static final int SUB_HEIGHT = 3;
public static void drawLine( ) {
System.out.print ("+");
for (int i=1; i <= (2*SUB_HEIGHT); i++) {
System.out.print (“-”); }
System.out.println (“+”);

13. drawTop ( ) using constant
// produces the top half of the hourglass figure
public class drawTop {
for (int line = 1; line <= SUB_HEIGHT; line++) { System.out.print (“|”);
for (int i = 1; i <= (line-1); i++) {
system.out.print(“ “); }
System.out.print (“\\”);
for (int i = 1; i <= ((2*SUB_HEIGHT)-2*line); i++) { system.out.print(“ “);
System.out.print (“/”);
System.out.print (“|”);

14. Rocket: Assignment #3 Write a java program to produce this output.
The height is 3; allow for the height to vary (with multiples of 3).
/**\
//**\\
///**\\\
////**\\\\
/////**\\\\\
+=*=*=*=*=*=*+
|../\..../\..|
|./\/\../\/\.|
|/\/\/\/\/\/\|
|\/\/\/\/\/\/|
|.\/\/..\/\/.|
|..\/....\/..|

15. Rocket: Assignment #3 Decomposition
/**\
//**\\
///**\\\
////**\\\\
/////**\\\\\
+=*=*=*=*=*=*+
|../\..../\..|
|./\/\../\/\.|
|/\/\/\/\/\/\|
|\/\/\/\/\/\/|
|.\/\/..\/\/.|
|..\/....\/..|

16. Rocket: Assignment #3 pseudocode
/**\
//**\\
///**\\\
////**\\\\
/////**\\\\\
+=*=*=*=*=*=*+
|../\..../\..|
|./\/\../\/\.|
|/\/\/\/\/\/\|
|\/\/\/\/\/\/|
|.\/\/..\/\/.|
|..\/....\/..|
drawCone ( );
drawLine ( );
drawM ( );
drawW ( );
drawLine ( );
drawW ( );
drawM ( );
drawLine ( );
drawCone ( );

17. In-Class Exercise Create pseudocode for drawCone( );
Create output table for drawCone( );
Write code for drawCone( );
Note: Use a constant for HEIGHT. Compute height and length based on HEIGHT.
Note: Top of rocket and booster of rocket are the same shape.