Structuring Data with Java - Java - page 282

return return null null ;

}
return

return stack [ depth - 1 ];

}

public public boolean boolean hasNext () {

return

return depth > 0 ;

}

public public boolean boolean hasRoom () {

return

return depth < stack . length ;

}

public public int int getStackDepth () {

return return depth ;

}

}

This version has a lot more error checking (and a unit test, in the src/test/java/structure
folder), as well as some additional methods not in the original (e.g., hasRoom() —unlike the
full-blown java.util.Stack , this one does not expand beyond its original size, so we need
a way to see if it is full without throwing an exception).

For an example of the “real” java.util.Stack in operation, Handling Very Large Numbers
provides a simple stack-based numeric calculator.

Multidimensional Structures

Problem

You need a two-, three-, or more dimensional array or ArrayList .

Solution

No problem. Java supports this.