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