数组中可被10整除的计数数

Question

我被分配了一个任务，让我创建3个方法来创建一个数组，打印一个数组，并计算一个数组中所有可被10整除的数字。给我最大麻烦的部分是数可被10整除的数字。这是我到目前为止的代码：

public int[] createArray(int size) {

    Random rnd = new Random();
    int[] array = new int[size];

    for (int i = 0; i < array.length; i++) {
        array[i] = rnd.nextInt(101);
    }
    return array; 
}

public void printArray() {

    Journal5a call = new Journal5a();
    int[] myArray = call.createArray(10);

    for (int i = 0; i < myArray.length; i++) {
        System.out.println(myArray[i]);
    }
    System.out.println("There are " + call.divideByTen(myArray[i]) + " numbers that are divisable by 10");
}

public int divideByTen(int num) {

    int count = 0;

    if (num % 10 == 0) {
        count++;
    }
    return count;        
}

public static void main(String[] args) {

    Journal5a call = new Journal5a();
    Random rnd = new Random();

    call.printArray();
}

Answer 1

将一个数组传递给该方法，并使用该数组确定计数。你的算法看起来很合理。就像，

public int divideByTen(int[] nums) {
    int count = 0;
    for (int num : nums) {
        if (num % 10 == 0) {
            count++;
        }
    }
    return count;
}

或者，在Java8+中，使用intstream和filter

return (int) IntStream.of(nums).filter(x -> x % 10 == 0).count();

然后你可以把它叫做

System.out.println("There are " + call.divideByTen(myArray) 
        + " numbers that are divisible by 10");

System.out.printf("There are %d numbers that are divisible by 10.%n", 
        IntStream.of(nums).filter(x -> x % 10 == 0).count());