Recursion Programs

Recursion
Recursion is a programming concept where a function calls itself to solve a problem step by step.

Example Programs
1) Java( Print 1 to 5)

           public class Main {
              public static void main(String[] args) {
        print(1);
    }

    static void print(int n) {
        if (n > 5) return;
        System.out.print(n + " ");
        print(n + 1);
    }
}

python

  def print_num(n):
    if n > 5:
        return
    print(n, end=" ")
    print_num(n + 1)

print_num(1)

Javascript

function printNum(n) {
  if (n > 5) return;
  console.log(n);
  printNum(n + 1);
}

printNum(1);

output

2) Java (Print 1,3,5,7,9)

 public class Main {
    public static void main(String[] args) {
        print(1);
    }

    static void print(int n) {
        if (n > 9) return;
        System.out.print(n + " ");
        print(n + 2);
    }
}

python

def print_num(n):
    if n > 9:
        return
    print(n, end=" ")
    print_num(n + 2)

print_num(1)

Javascript

 function printNum(n) {
  if (n > 9) return;
  console.log(n);
  printNum(n + 2);
}

printNum(1);

output

3) Java (Print 5,10,15,20,25)

 public class Main {
    public static void main(String[] args) {
        print(5);
    }

    static void print(int n) {
        if (n > 25) return;
        System.out.print(n + " ");
        print(n + 5);
    }
}

python

def print_num(n):
    if n > 25:
        return
    print(n, end=" ")
    print_num(n + 5)

print_num(5)

javascript

 function printNum(n) {
  if (n > 25) return;
  console.log(n);
  printNum(n + 5);
}

printNum(5);

output

4) java (Factorial)

public class Main {
    public static void main(String[] args) {
        int result = fact(5);
        System.out.println(result);
    }

    static int fact(int n) {
        if (n == 1) return 1;   
        return n * fact(n - 1); 
    }
}

python

def fact(n):
    if n == 1:
        return 1
    return n * fact(n - 1)

print(fact(5))

javascript

 function fact(n) {
  if (n === 1) return 1;
  return n * fact(n - 1);
}

console.log(fact(5));

output