为什么这个 return false 对于给定的数组

Question

int[] array2 = new int[]{1,2,6,6,3,1,};
//method checks if the given array contents remain the same when array is reversed
public static boolean verify(int[] array, int index) {//method takes array and an index number

    if ((array[index] == array[array.length - index-1]) && (index < array.length/2)) {
        System.out.print("true/");
        verify(array, ++index);// increase index number to check the next values in the th array
        return true;
    } else
        System.out.println("..false..");
        return false;
    }

Answer 1

您可能想做这样的事情：

public static boolean verify(int[] array, int index) {

    if (array[index] == array[array.length - index-1]) {
        if(index < array.length/2)
            return verify(array, ++index);
        return true;
    } else {...}
    return false;
}

您需要确保子值传播到父值，并以不同方式检查索引：没有错，如果索引超过数组长度的一半，您只是不想检查此类索引的值。

Answer 2

最好不要在方法中打印结果，而只打印 return 值。

public static boolean verify(int[] array, int index) {
    // don't go passed the middle
    if (index >= array.length/2) {
        return true;
    }
    // return as soon as a false comparison is found
    if(array[index] != array[array.length-index-1]) {
        return false;
    }
    // Try the next value
    return verify(array, index + 1);
}

System.out.println(verify(new int[] {1,2,3,3,3,2,1}, 0));
System.out.println(verify(new int[] {1,2,3,3,2,1}, 0));
System.out.println(verify(new int[] {1,2,4,3,3,2,1}, 0));
System.out.println(verify(new int[] {1,2,4,3,3,4,2,1}, 0));
System.out.println(verify(new int[] {1}, 0));
System.out.println(verify(new int[] {1,2}, 0));

版画

true
true
false
true
true
false

为什么这个 return false 对于给定的数组

why wont this return false with the given array

java

recursion

boolean-logic

return