http://javabat.com is a fun and exciting place to practice recursion. Their examples start fairly light and work through extensive (if you want to take it that far). Note: Their approach is learn by practicing. Here is a recursive function that I wrote to simply replace a for loop.
The for loop:
public printBar(length)
{
String holder = "";
for (int index = 0; i < length; i++)
{
holder += "*"
}
return holder;
}
Here is the recursion to do the same thing. (notice we overload the first method to make sure it is used just like above). We also have another method to maintain our index (similar to the way the for statement does it for you above). The recursive function must maintain their own index.
public String printBar(int Length) // Method, to call the recursive function
{
printBar(length, 0);
}
public String printBar(int length, int index) //Overloaded recursive method
{
// To get a better idea of how this works without a for loop
// you can also replace this if/else with the for loop and
// operationally, it should do the same thing.
if (index >= length)
return "";
else
return "*" + printBar(length, index + 1); // Make recursive call
}
To make a long story short, recursion is a good way to write less code. In the latter printBar notice that we have an if statement. IF our condition has been reached, we will exit the recursion and return to the previous method, which returns to the previous method, etc. If I sent in a printBar(8), I get ********. I am hoping that with an example of a simple function that does the same thing as a for loop that maybe this will help. You can practice this more at Java Bat though.
