当我在 for 循环内迭代数组元素时，如何迭代 Java 中的数组元素？

Question

我正在学习 java，正在学习 Java 中的 arrays。我想尝试编写一个程序来遍历数组中的每个元素，并使用程序查看元素是增加、减少还是数组的一部分正在增加的方法并且数组的一部分正在减少。 我对如何执行此操作感到很困惑，并希望获得有关我需要修复的内容的一些指导。 我猜我的尝试可能与我想要发生的事情相去甚远。

我不太确定如何遍历数组并测试每个单独的元素。 我试过了，但我做错了。 我试图制作一个 for 循环，它将遍历数组的元素。 在 for 循环中，我尝试制作一个 if 语句，我希望它通过数组中的每个元素到 go，然后检查数组的顺序是否为递增顺序，然后是 output“递增”、递减顺序和 output“递减” ”，或者如果数组的一部分在增加而一部分在减少，我希望 output 是“增加和减少”。 （例如：{1,3,5,7,4,2}）1,3,5,7 增加，4,2 减少。 所以我有一个循环来遍历数组中的每个元素，然后在第一个循环中进行另一个循环，检查数组中的元素是增加还是减少，并输出增加或减少。

public class increasingOrDecreasing {
    public static void main(String[] args) {

        int[] array1 = { 3, 8, 13, 29, 52, 81 };

        int[] array2 = { 77, 66, 55, 33, 22, 11 };

        int[] array3 = { 20, 30, 60, 40, 15, 2 };

        int[] array4 = { 10, 30, 50, 50, 60, 80 };

        // call the method
        increaseOrDecrease(array1);
        increaseOrDecrease(array2);
        increaseOrDecrease(array3);
        increaseOrDecrease(array4);
    }

    // create the method

    public static int increaseOrDecrease(int[] myArray) {
        // make a loop to check if all the integers of the array are in either
        // increasing or decreasing order or both


        for (int i = 0; i < myArray.length; i++) {

            // if the array is increasing
// What I wanted is for it to start at array i = 0 and have [i] go up by 1 until it loops through the end // of the array. Then if each element is less than the subsequent element it would output "Increasing": I // did not do this correctly and would like some help. I guess all I did is check if myArray[i] is less 
// than myArray[i+1]

// if the array was {1, 3, 6, 8} then the method would go through each element and find that index [0] < 
// index [1] and index[1] < index [2] and index[2] < index [3] and output Increasing and return a value of // 1 because the method would find that all the numbers are ordered smallest to largest.


            if (myArray[i] < myArray[i++]) {


                System.out.println("Increasing");
                return 1;
            }

// this is incorrect and does not do what I was hoping it would.
            // if the array is decreasing
            else if (myArray[i] > myArray[i++]) {
                System.out.println("Decreasing");
                return 2;
            }


// this is also incorrect
            // if the array is increasing and decreasing
            else (myArray[i] < myArray[i++] && myArray[i] > myArray[i++]) {
                System.out.println("Both increasing and decreasing");
                return 3;
            }
        }
        return 0;

    }

}

这就是我想要的：检查每个元素并查看该元素是否小于数组中的下一个元素。 对于第一个数组 {3,8,17,25,89,94} 它将遍历数组。 索引 0 是 3，小于索引 1。它转到元素 1，即 8，索引 1 小于索引 2，即 17。这种情况会一直发生，直到该方法循环遍历数组中的所有元素，它会 output增加。 如果数组中的每个元素都小于后续元素，则检查顺序是否从最小到最大，然后该方法将 output 递增。 然后，如果数组仅反向减少，我会做同样的事情。 我没有正确执行此操作，请提供帮助。

这是我尝试检查数组是否从最小到最大的方法。 我认为它只是检查了 if [i] < [i++] 但没有通过整个数组检查 go 。

      for (int i = 0; i < myArray.length; i++) {

            // if the array is increasing
// What I wanted is for it to start at array i = 0 and have [i] go up by 1 until it loops through the end // of the array. Then if each element is less than the subsequent element it would output "Increasing": I // did not do this correctly and would like some help. I guess all I did is check if myArray[i] is less 
// than myArray[i+1]

// if the array was {1, 3, 6, 8} then the method would go through each element and find that index [0] < 
// index [1] and index[1] < index [2] and index[2] < index [3] and output Increasing and return a value of // 1 because the method would find that all the numbers are ordered smallest to largest.


            if (myArray[i] < myArray[i++]) {


                System.out.println("Increasing");
                return 1;
            }

Answer 1

public class Eli {
   
    public static void main(String[] args) {
        int myArray[] = {12,5,4,7,2};
        boolean increasing = false, decreasing = false;
        for (int i = 0; i < myArray.length-1; i++) {
            
            if (myArray[i] < myArray[i+1]) {
                increasing = true;
            }
            if (myArray[i] > myArray[i+1]) {
                decreasing = true;
            }

        }
        if (increasing == true && decreasing == true) {
            System.out.println("Increasing and decreasing");
        }
        else {
            if (increasing == true)
                System.out.println("Increasing");
            else System.out.println("Decreasing");
        }

    }
}

注意：如果您确定下跌后上涨不被视为“上涨和下跌”，则循环中的第一个条件将是：

if (decreasing == true)
    break;