Recursion programs added

Author: muskanmi

recursion/Lucky.java

@@ -0,0 +1,21 @@
+package recursion;
+
+public class Lucky {
+    boolean isLucky(int n){
+        int counter = 2;
+        if(counter > n) {
+            return true;
+        }
+        if(n%counter == 0) {
+            return false;
+        }
+        int np = n;
+        np = np - np / counter;
+        counter++;
+        return isLucky(np);
+    }
+    public static void main(String[] args) {
+        Lucky obj = new Lucky();
+        System.out.println(obj.isLucky(13));
+    }
+}

recursion/Phone.java

@@ -0,0 +1,21 @@
+package recursion;
+public class test {
+    public static String[] keypad = {".", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tu", "vwx", "yz"};
+
+    public static void printComb(String str, int index, String combination) {
+        if(index == str.length()) {
+            System.out.print(combination + " ");
+            return;
+        }
+        char currChar = str.charAt(index);
+        String mapping = keypad[currChar - '0'];
+
+        for(int i=0; i<mapping.length(); i++) {
+            printComb(str, index+1, combination + mapping.charAt(i));
+        }
+    }
+    public static void main(String[] args) {
+        String str = "23";
+        printComb(str, 0, "");
+    }
+}