Recursion in Java

by Online Tutorials Library July 14, 2022

Recursion in Java

Recursion in java is a process in which a method calls itself continuously. A method in java that calls itself is called recursive method.

It makes the code compact but complex to understand.

Syntax:

 returntype methodname(){ //code to be executed methodname();//calling same method } 

Java Recursion Example 1: Infinite times

 public class RecursionExample1 { static void p(){ System.out.println(“hello”); p(); }  public static void main(String[] args) { p(); } } 

Output:

hello hello ... java.lang.StackOverflowError

Java Recursion Example 2: Finite times

 public class RecursionExample2 { static int count=0; static void p(){ count++; if(count<=5){ System.out.println(“hello “+count); p(); } } public static void main(String[] args) { p(); } } 

Output:

hello 1 hello 2 hello 3 hello 4 hello 5

Java Recursion Example 3: Factorial Number

 public class RecursionExample3 { static int factorial(int n){       if (n == 1)         return 1;       else         return(n * factorial(n-1));     }      public static void main(String[] args) { System.out.println(“Factorial of 5 is: “+factorial(5)); } } 

Output:

Factorial of 5 is: 120

Working of above program:

factorial(5)     factorial(4)        factorial(3)           factorial(2)              factorial(1)                 return 1              return 2*1 = 2           return 3*2 = 6        return 4*6 = 24     return 5*24 = 120

Java Recursion Example 4: Fibonacci Series

 public class RecursionExample4 { static int n1=0,n2=1,n3=0;      static void printFibo(int count){         if(count>0){              n3 = n1 + n2;              n1 = n2;              n2 = n3;              System.out.print(” “+n3);             printFibo(count-1);          }      }        public static void main(String[] args) { int count=15;       System.out.print(n1+” “+n2);//printing 0 and 1       printFibo(count-2);//n-2 because 2 numbers are already printed    } } 

Output:

0 1 1 2 3 5 8 13 21 34 55 89 144 233 377

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Recursion in Java

Recursion in Java

Java Recursion Example 1: Infinite times

Java Recursion Example 2: Finite times

Java Recursion Example 3: Factorial Number

Java Recursion Example 4: Fibonacci Series

Difference between Method Overloading and Method Overriding in java

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