In normal recursion, operations are performed with the returned values whereas in tail recursion no operation is to be performed since it deals with the last statement. One main advantage of using tail recursion is that it reduces the complexity of the function.
If normal recursion is considered the address needs to be stored in the stack whereas the main advantage of using tail recursion is that since it is the last operation in a function, it does not need to be stored in the stack.
In this article, we will discuss the implementation of tail recursion in Java.
How to Implement Tail Recursion in Java?
Languages like Java, Python, and C++ do not typically support tail recursion since the values are kept in the stack and are called according to the need. While the tail recursion needs no further computation at all. Haskell and Scala are the programming languages that best utilize tail recursion. Tail recursion in Java is implemented in such a way that it is declared with some other function.
Let us also make this clear by implementing factorial using the normal recursion process and implementing it using the tail recursion in Java
Example 1: Normal Recursion for Factorial of a Number
The following code illustrates how the normal recursion finds the factorial of a number in Java:
//Declare a factorial classclass factorial {
static int fact(int n)
{//Initialize to 0
if (n == 0)
return 1;
//The factorial function.
return n*fact(n - 1);
}//The main class
static public void main(String[] args)
{
System.out.println(fact(6));
}
}
In the above code:
- A function named fact is declared.
- This function in the next step decreases the value by 1 until it reaches the specified value.
- The factorial has been returned using the function.
Output
Example 2: Tail Recursion For Factorial Of a Number
The following code illustrates how the tail recursion finds the factorial of a number in Java:
//declare a classclass tailfactorial {
static int tailfact(int n, int x)
{
if (n <= 0)
return x;
return tailfact(n - 1, n * x);
}
static int fact(int n) { return tailfact(n, 1); }
static public void main(String[] args)
{
System.out.println(fact(6));
}
}
In the above code
- A function named tailfact is declared.
- This function tailfact declared within the fact() function that will eventually return the factorial of the declared value.
Output
In the following output, the factorial of the value 6 appears to be 720:
That’s all about the implementation of tail recursion in Java.
Conclusion
Tail recursion occurs when a recursive call is made and ends afterward and has nothing to perform after the completion of this recursive call. The factorial method follows recursion therefore the factorial program has demonstrated the implementation of tail recursion. This write-up has effectively demonstrated the implementation of tail recursion in Java.