java recursion

1    public static  int exponent(int n){
2        int ans;
3        if(n == 0)
4            return 1;
5        else if(n%2 == 0){
6            int k = exponent(n/2);
7            ans = k*k;
8        }
9        ans= 2 * exponent(n-1);
10
11        return ans ;
12    }
13

1class scratch{
2    public static long factorial(int n){
3        if ( n == 1 ){
4            return 1;
5        }
6        else{
7            return n * factorial( n - 1 );
8        }
9    }
10    public static void main(String[] args) {
11        System.out.println( factorial(5) );
12        //Print 120 (5!) to the console
13    }
14}

1// prints x number of $
2public static void recursion(int x) {
3  if(x == 0) { // base case
4    System.out.println();
5  } else { // recursive case
6    System.out.print("$");
7    recursion(x - 1);
8  }
9}

1Recursion is a basic programming technique
2you can use in Java, in which a method
3calls itself to solve some problem. 
4  A method that uses this technique
5  is recursive. Many programming problems
6  can be solved only by recursion,
7and some problems that can be solved by
8other techniques are better solved by recursion.
9
10EXP-1: Factorial
11	
12	public static long factorial(int n){
13        if (n == 1)
14            return 1;
15        else
16            return n * factorial(n-1);
17    }
18
19EXP-2: Fibonacci
20	
21	static int n1=1, n2=2, n3=0;
22    public static void printFibo(int count){
23        if (count > 0) {
24            n3 = n1 + n2;
25            n1 = n2;
26            n2 = n3;
27            System.out.print(" " + n3);
28            printFibo(count-1);
29        }
30    }

1import java.util.Scanner;
2
3public class SumDigit {
4    public static void main(String[] argh){
5        System.out.println("Enter int");
6        Scanner input = new Scanner(System.in);
7        int n = input.nextInt();
8        int sum = 0 ;
9        int i = 0;
10        print( i =Sum_of_digits(sum,n));
11
12    }
13
14    public static int Sum_of_digits(int sum,int n){
15        if(n<=0)
16            return sum ;
17        sum += n%10;
18
19        return Sum_of_digits(sum,n/10);
20    }
21
22    public static void  print(int n){
23        System.out.print(n);
24    }
25}
26

1public void removeDigits(String string) {
2  if(string.length == 1) {
3    if(Character.isDigit(string.CharAt(0))) {
4      return "";
5    } else {
6      return string;
7    }
8  } else {
9    if(Character.isDigit(string.CharAt(0))) {
10      return removeDigits(string.substring(1));
11    } else {
12      return string.substring(0, 1) + removeDigits(string.substring(1));
13
14public static void main(String[] args) {
15  String string = "1a2b3c"
16  System.out.println(removeDigits(string)); //will print "abc"
17}