Computer-Science-2/PerfectNumberFinder.java at main · ChristopherMathematica/Computer-Science-2 · GitHub

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/* Christopher Yonek
CSC-164-651 - Mr. Ng
2/22/2020
Test 1: This program takes two numbers from a user and finds the perfect number between the specified range
 */
importcom.sun.jdi.IntegerValue;
importjava.math.BigInteger;
importjava.util.Scanner;
importjava.math.*;

publicclassPerfectNumberFinder {
publicstaticvoidmain(String[] args) {
intgoAgain = - 1;
intuserNumExit = 0;
while(goAgain != userNumExit) {
ScanneruserInput = newScanner(System.in);
System.out.println("Please Enter a positive number(preferably the min.) : ");
longuserNum1 = userInput.nextLong();
System.out.println("Please Enter a positive number(preferably the max.): ");
longuserNum2 = userInput.nextLong(); // 2nd input
PerfectNumberGenerator(RangeBetweenNumbers(userNum1, userNum2));
System.out.println("Would you like to go again?, Enter -1 to exit");
userNumExit = userInput.nextInt();
 }
System.out.println("Thank you for using perfect number finder!");
System.exit(0);
 }
publicstaticlongRangeBetweenNumbers(longuserNum1, longuserNum2) {
longrangeForNums = 0;
if (userNum1>userNum2){
rangeForNums = userNum1 - userNum2;
 }
if (userNum2>userNum1){
rangeForNums = userNum2 - userNum1;
 }
if (userNum1==userNum2){
System.out.println("Please enter two different numbers!");
System.exit(0);
 }
returnrangeForNums;
 }


publicstaticbooleanTestIfPrime(intpossiblePrime) {
intvalueRemainder;
for (inti = 2; i <= possiblePrime / 2; i++) {
valueRemainder = possiblePrime % i;
//if remainder is 0 than possiblePrime is not prime!
if (valueRemainder == 0) {
returnfalse;
 }
 }
returntrue;
 }


publicstaticvoidPerfectNumberGenerator(longrange) { ;
booleanyesPrime = true;
//Empty String
StringprimeNumbersFound = "";

//Start loop 1 to maxCheck
//THINGY i <= rangeMax
for (inti = 1; i <= range; i++) {
yesPrime = TestIfPrime(i);
if (yesPrime) {
primeNumbersFound = primeNumbersFound + i + " ";
 }
 }

//Turn entered string into an Array of primes
String[] brokenApart = primeNumbersFound.split(" ");
long[] primeIntNumbers = newlong[brokenApart.length];

//Create BigInteger variables for precision
BigInteger[] allPrimes = newBigInteger[primeIntNumbers.length];
BigIntegerlowValue = BigInteger.valueOf(1);

System.out.println("Your perfect numbers are: ");
for (inti = 0; i < brokenApart.length; i++) {
//change prime numbers from string to long

primeIntNumbers[i] = Long.parseLong(brokenApart[i]);
//change long into big integer
allPrimes[i] = BigDecimal.valueOf(primeIntNumbers[i]).toBigInteger();

//If-statement to remove 1 from Perfect Number set
if (primeIntNumbers[i] != 1) {
//operations on BigInteger numbers to get list of possible perfect numbers
BigIntegerdifferenceAnswer = allPrimes[i].subtract(lowValue);
BigIntegereqnPtOne = BigPower(BigInteger.valueOf(2), differenceAnswer);
BigIntegereqnPtTwo = BigPower(BigInteger.valueOf(2), allPrimes[i]).subtract(lowValue);
BigIntegerproductAnswer = eqnPtOne.multiply(eqnPtTwo);
CheckIfPerfect(range, productAnswer);
 }
 }
 }

publicstaticBigIntegerBigPower(BigIntegerbaseNum, BigIntegerexponent) {
BigIntegerresultExp = BigInteger.ONE;
while (exponent.signum() > 0) {
if (exponent.testBit(0)) resultExp = resultExp.multiply(baseNum);
baseNum = baseNum.multiply(baseNum);
exponent = exponent.shiftRight(1);
 }
returnresultExp;
 }

publicstaticvoidCheckIfPerfect(longspecifiedRange, BigIntegerperfectResult) {
intsum = 0;
for (inti = 1; BigInteger.valueOf(i).compareTo(perfectResult) < 0; i++) {
if ((perfectResult.mod(BigInteger.valueOf(i))).equals(BigInteger.ZERO)) {
sum = sum + i;
if(perfectResult.mod(BigInteger.valueOf(i)).compareTo(BigInteger.ZERO) > 0){
break;
 }
 }
 }
if (perfectResult.compareTo(BigInteger.valueOf(specifiedRange))<0) {
if (BigInteger.valueOf(sum).equals(perfectResult)) {
System.out.println(perfectResult);
 }
 }
 }
}