public static boolean isInteger(String str) { if (str == null) { return false; } int length = str.length(); int i = 0; // set the length and value for highest positive int or lowest negative int int maxlength = 10; String maxnum = String.valueOf(Integer.MAX_VALUE); if (str.c...
publicclassPositiveIntegerCheck{publicstaticbooleanisPositiveInteger(Objectnumber){if(numberinstanceofInteger){return(Integer)number>0;}returnfalse;}publicstaticvoidmain(String[]args){System.out.println(isPositiveInteger(5));// 输出: trueSystem.out.println(isPositiveInteger(-3));// 输出: falseSystem....
Write a program to check if a number is a Mersenne number or not. In mathematics, a Mersenne number is a number that can be written in the form M(n) = 2n− 1 for some integer n. The first four Mersenne primes are 3, 7, 31, and 127 Test Data Input a number: 127 Pictorial P...
Perhaps the easiest and the most reliable way to check whether a String is numeric or not is by parsing it using Java’s built-in methods: Integer.parseInt(String) Float.parseFloat(String) Double.parseDouble(String) Long.parseLong(String) new BigInteger(String) If these methods don’t throw ...
classHappyNumberDecider{publicstaticbooleanisHappyNumber(intn){ Set<Integer> checkedNumbers =newHashSet<>();while(true) { n = sumDigitsSquare(n);if(n ==1) {returntrue; }if(checkedNumbers.contains(n)) {returnfalse; } checkedNumbers.add(n); ...
Check Happy or Unhappy Number Write a Java program to check whether a given number is a happy number or unhappy number. Happy number: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1, or it ...
int number = r.nextInt(100) + 1;//r.nextInt(100)指的是在1~99随机,所以要加一 arr[i] = number; sum += arr[i]; } int average = sum / 10; int count = 0; for ( int i = 0; i < arr.length; i++) { if (arr[i] < average) { ...
@Data@AllArgsConstructor@NoArgsConstructorpublicclassUser{privateInteger id;@NotNull(message = "user对象中的username不能为空")privateString username; } 2.3.6 场景:分组校验 如果同一个类,在不同的使用场景下有不同的校验规则,那么可以使用分组校验。实际需求,如未成年人是不能喝酒,如何校验?
@TestpublicvoidtestIsPrime(){int number=10;Boolean isPrime=number>1&&IntStream.rangeClosed(2,(int)Math.sqrt(number)).noneMatch(n->(number%n==0));logger.debug(" {} Prime CORE Check is - [{}]",number,isPrime);logger.debug(" {} Prime BigInteger Check is - [{}]",number,BigInteger....
private final AtomicInteger ctl = new AtomicInteger(ctlOf(RUNNING, 0)); private static final int COUNT_BITS = Integer.SIZE - 3; private static final int CAPACITY = (1 << COUNT_BITS) - 1; // runState is stored in the high-order bits private static final int RUNNING = -1 << COUNT_...