30-Days-of-Code 30 days of Java programming challenge Day Questions 01 Write a function that takes in a number and return true if the number is even, false if it is odd. 02 Write a function that takes in a string and return true if the string is empty, false otherwise. 03 Write a function that checks if a given number is prime or not. 04 Write a function that takes in an array of numbers and returns the sum of the numbers. 05 Write a function that checks if a number is positive or negative. 06 Write a function that finds the maximun and minimum number in an array. 07 Write a function that sorts an array of numbers in ascending or descending order. 08 Write a function that finds the factorial of a given number. 09 Write a function that returns the length of a given string. 10 Write a function that checks if a given number is a multiple of both 3 and 5 11 Write a function that checks the given year is a leap year or not. 12 Write a function that takes in a number and print the fibonacci series till the number. 13 Write a function that search an element in an array. 14 Write a function that converts a string to uppercase. 15 Write a function that converts a string to lowercase. 16 Write a function that checks the given input character is vowel or consonent . 17 Write a function that reverse a number. 18 Write a function that find the duplicate characters in a string. 19 Write a function that copy all elements of one array into second array. 20 Write a function that calculate the square root of the given number. 21 Write a function that remove spaces from a String. 22 Write a function that count the number of vowels, consonants, and spaces in that string. 23 Write a function that calculate the area of the circle. 24 Write a function that check the number is Armstrong number or not. 25 Write a function that find the missing number in array. 26 Write a function that swap two numbers. 27 Write a function that find the greater number among the four number. 28 Write a function that Find the longest word. 29 Write a function that print the number triangle pattern. 30 Write a function that print the Rhombus Pattern.