[OCAJP]for迴圈4

Given the code fragment:

int[] array = {1, 2, 3, 4, 5};

And given the requirements:

Which two statements are true?

A. Requirements 1, 2, and 3 can be implemented by using the enhanced for loop.
B. Requirements 1, 2, and 3 can be implemented by using the standard for loop.
C. Requirements 2 and 3 CANNOT be implemented by using the standard for loop.
D. Requirement 1 can be implemented by using the enhanced for loop.
E. Requirement 3 CANNOT be implemented by using either the enhanced for loop or the standard for loop.

題解

需求1，按照順序走訪array陣列物件可以使用標準的for loop或是增強的for loop(即foreach)來實作出來。程式如下：

for(int i = 0; i < array.length; ++i){
    int number = array[i];
}
for(int number : array){
}

需求2，反向走訪array陣列物件只可以使用標準的for loop來實作。

for(int i = array.length - 1; i >= 0; --i){
    int number = array[i];
}

需求3，使用標準的for loop，可以間格走訪array陣列物件，實作方式如下：

for(int i = 0; i < array.length; i += 2){
    int number = array[i];
}

所以選項B和選項D的敘述是正確的。