Finite and Infinite Recursion with examples (original) (raw)

Last Updated : 23 Jul, 2025

The process in which a function calls itself directly or indirectly is called Recursion and the corresponding function is called a Recursive function.
Using Recursion, certain problems can be solved quite easily. Examples of such problems are Towers of Hanoi (TOH), Inorder/Preorder/Postorder Tree Traversals, DFS, etc.

Types of Recursions:

Recursion can be further classified into two kinds, depending on when they terminate:

1. Finite Recursion
2. Infinite Recursion

Finite Recursion:

Finite Recursion occurs when the recursion terminates after a finite number of recursive calls. A recursion terminates only when a base condition is met.

Example:

Below is an implementation to demonstrate Finite Recursion.

C++ `

// C++ program to demsonstrate Finite Recursion #include <bits/stdc++.h> using namespace std;

// Recursive function void Geek(int N) { // Base condition // When this condition is met, // the recursion terminates if (N == 0) return;

// Print the current value of N
cout << N << " ";

// Call itself recursively
Geek(N - 1);

}

// Driver code int main() {

// Initial value of N
int N = 5;

// Call the recursive function
Geek(N);
return 0;

}

Java

// Java program for the above approach class GFG{

// Recursive function static void Geek(int N) {

// Base condition
// When this condition is met,
// the recursion terminates
if (N == 0)
    return;

// Print the current value of N
System.out.println(N + " ");

// Call itself recursively
Geek(N - 1);

}

// Driver code public static void main(String[] args) {

// Initial value of N
int N = 5;

// Call the recursive function
Geek(N);

} }

// This code is contributed by abhinavjain194

Python3

Python program to demsonstrate Finite Recursion

Recursive function

def Geek( N):

# Base condition
# When this condition is met,
# the recursion terminates
if (N == 0):
    return

# Pr the current value of N
print( N, end =" " )

# Call itself recursively
Geek(N - 1)

Driver code

Initial value of N

N = 5

Call the recursive function

Geek(N)

this code is contributed by shivanisinghss2110

C#

// C# program for the above approach using System; using System.Collections.Generic;

class GFG{

// Recursive function static void Geek(int N) {

// Base condition
// When this condition is met,
// the recursion terminates
if (N == 0)
    return;

// Print the current value of N
Console.Write(N + " ");

// Call itself recursively
Geek(N - 1);

}

// Driver Code public static void Main(String[] args) {

// Initial value of N
int N = 5;

// Call the recursive function
Geek(N);

} }

// This code is contributed by target_2.

JavaScript

`

Time Complexity: O(n)
Auxiliary Space: O(n)

The recursion tree for the above recursive function looks like this.

Recursion Tree

When the value of N becomes 0, because of the base condition, the recursion terminates.

Infinite Recursion:

Infinite Recursion occurs when the recursion does not terminate after a finite number of recursive calls. As the base condition is never met, the recursion carries on infinitely.

Example:

Below is an implementation to demonstrate Infinite Recursion.

C++ `

// C++ program to demsonstrate Infinite Recursion #include <bits/stdc++.h> using namespace std;

// Recursive function void Geek(int N) { // Base condition // This condition is never met here if (N == 0) return;

// Print the current value of N
cout << N << " ";

// Call itself recursively
Geek(N);

}

// Driver code int main() {

// Initial value of N
int N = 5;

// Call the recursive function
Geek(N);
return 0;

}

Java

// Java program to demsonstrate Infinite Recursion import java.io.*;

class GFG { // Recursive function static void Geek(int N) { // Base condition // This condition is never met here if (N == 0) return;

// Print the current value of N
System.out.print( N +" ");

// Call itself recursively
Geek(N);

}

// Driver code public static void main(String[] args) {

// Initial value of N
int N = 5;

// Call the recursive function
Geek(N);
}

}

// This code is contributed by shivanisinghss2110

Python3

Python3 to demsonstrate Infinite Recursion

Recursive function

def Geek(N):

# Base condition
# This condition is never met here
if (N == 0):
    return

# Print the current value of N
print(N, end = " " )

# Call itself recursively
Geek(N)

Driver code

Initial value of N

N = 5

Call the recursive function

Geek(N)

This code is contributed by shivanisinghss2110

C#

// C# program to demsonstrate Infinite Recursion using System;

class GFG { // Recursive function static void Geek(int N) { // Base condition // This condition is never met here if (N == 0) return;

// Print the current value of N
Console.Write( N +" ");

// Call itself recursively
Geek(N);

}

// Driver code public static void Main(String[] args) {

// Initial value of N
int N = 5;

// Call the recursive function
Geek(N);
}

}

// This code is contributed by shivanisinghss2110

JavaScript

`

Time Complexity: non finite as this recursion will never end.
Auxiliary Space: non finite

The recursion tree for the above recursive function looks like this.

Recursion Tree

Since the value of N never becomes 0, so the recursion never terminates. Instead, the recursion continues until the implicit stack becomes full which results in a Stack Overflow. Some compilers directly give the output as Segmentation Fault (Core Dumped), while others may abnormally terminate for some value and then show Segmentation fault.