Initial data commit

Task/Factorial/Java/factorial-1.java

@@ -0,0 +1,53 @@
+package programas;
+
+import java.math.BigInteger;
+import java.util.InputMismatchException;
+import java.util.Scanner;
+
+public class IterativeFactorial {
+
+  public BigInteger factorial(BigInteger n) {
+    if ( n == null ) {
+      throw new IllegalArgumentException();
+    }
+    else if ( n.signum() == - 1 ) {
+      // negative
+      throw new IllegalArgumentException("Argument must be a non-negative integer");
+    }
+    else {
+      BigInteger factorial = BigInteger.ONE;
+      for ( BigInteger i = BigInteger.ONE; i.compareTo(n) < 1; i = i.add(BigInteger.ONE) ) {
+        factorial = factorial.multiply(i);
+      }
+      return factorial;
+    }
+  }
+
+  public static void main(String[] args) {
+    Scanner scanner = new Scanner(System.in);
+    BigInteger number, result;
+    boolean error = false;
+    System.out.println("FACTORIAL OF A NUMBER");
+    do {
+      System.out.println("Enter a number:");
+      try {
+        number = scanner.nextBigInteger();
+        result = new IterativeFactorial().factorial(number);
+        error = false;
+        System.out.println("Factorial of " + number + ": " + result);
+      }
+      catch ( InputMismatchException e ) {
+        error = true;
+        scanner.nextLine();
+      }
+
+      catch ( IllegalArgumentException e ) {
+        error = true;
+        scanner.nextLine();
+      }
+    }
+    while ( error );
+    scanner.close();
+  }
+
+}

Task/Factorial/Java/factorial-2.java

@@ -0,0 +1,56 @@
+package programas;
+
+import java.math.BigInteger;
+import java.util.InputMismatchException;
+import java.util.Scanner;
+
+public class RecursiveFactorial {
+
+  public BigInteger factorial(BigInteger n) {
+    if ( n == null ) {
+      throw new IllegalArgumentException();
+    }
+
+    else if ( n.equals(BigInteger.ZERO) ) {
+      return BigInteger.ONE;
+    }
+    else if ( n.signum() == - 1 ) {
+      // negative
+      throw new IllegalArgumentException("Argument must be a non-negative integer");
+    }
+    else {
+      return n.equals(BigInteger.ONE)
+          ? BigInteger.ONE
+          : factorial(n.subtract(BigInteger.ONE)).multiply(n);
+    }
+  }
+
+  public static void main(String[] args) {
+    Scanner scanner = new Scanner(System.in);
+    BigInteger number, result;
+    boolean error = false;
+    System.out.println("FACTORIAL OF A NUMBER");
+    do {
+      System.out.println("Enter a number:");
+      try {
+        number = scanner.nextBigInteger();
+        result = new RecursiveFactorial().factorial(number);
+        error = false;
+        System.out.println("Factorial of " + number + ": " + result);
+      }
+      catch ( InputMismatchException e ) {
+        error = true;
+        scanner.nextLine();
+      }
+
+      catch ( IllegalArgumentException e ) {
+        error = true;
+        scanner.nextLine();
+      }
+    }
+    while ( error );
+    scanner.close();
+
+  }
+
+}

Task/Factorial/Java/factorial-3.java

@@ -0,0 +1,37 @@
+import java.math.BigInteger;
+import java.util.InputMismatchException;
+import java.util.Scanner;
+
+public class LargeFactorial {
+    public static long userInput;
+    public static void main(String[]args){
+        Scanner input = new Scanner(System.in);
+        System.out.println("Input factorial integer base: ");
+        try {
+            userInput = input.nextLong();
+            System.out.println(userInput + "! is\n" + factorial(userInput) + " using standard factorial method.");
+            System.out.println(userInput + "! is\n" + factorialRec(userInput) + " using recursion method.");
+        }catch(InputMismatchException x){
+            System.out.println("Please give integral numbers.");
+        }catch(StackOverflowError ex){
+            if(userInput > 0) {
+                System.out.println("Number too big.");
+            }else{
+                System.out.println("Please give non-negative(positive) numbers.");
+            }
+        }finally {
+            System.exit(0);
+        }
+    }
+    public static BigInteger factorialRec(long n){
+        BigInteger result = BigInteger.ONE;
+        return n == 0 ? result : result.multiply(BigInteger.valueOf(n)).multiply(factorial(n-1));
+    }
+    public static BigInteger factorial(long n){
+        BigInteger result = BigInteger.ONE;
+        for(int i = 1; i <= n; i++){
+            result = result.multiply(BigInteger.valueOf(i));
+        }
+        return result;
+    }
+}