Java是否针对基元精确定义的迭代顺序？

问题描述

示例代码：

  int a [] = new int [] {0，1，2，3}; 
 int result = 0; 
 for（int i：a）
 result + = i; 
  

循环保证迭代 a [0] ， a [1] ， a [2] ， a [3] 按顺序？我坚信，答案是肯定的，但 a>似乎没有明确的状态顺序。

得到了一个可靠的参考吗？

解决方案

  int [] array = a; 
 for（int index = 0; index< a.length; index ++）{
 int i = array [index]; 
结果+ = i; 
 
  

其中 array 和 index 是编译器生成的标识符，与其他标识符（编译器生成的或其他标识符）不同，这些标识符位于增强的为语句发生。 （在这里稍微解释变量名称）。

所以是的：订单是绝对有保证的。

Example code:

int a[] = new int[]{0, 1, 2, 3};
int result = 0;
for (int i : a)
    result += i;

Is the loop guaranteed to iterate across a[0], a[1], a[2], a[3] in that order? I strongly believe the answer is yes, but this page seems to not unambiguously state order.

Got a solid reference?

解决方案

According to the JLS, The enhanced for statement, your for-loop is equivalent to

int[] array = a;
for (int index = 0; index < a.length; index++) {
    int i = array[index];
    result += i;
}

"where array and index are compiler-generated identifiers that are distinct from any other identifiers (compiler-generated or otherwise) that are in scope at the point where the enhanced for statement occurs." (slightly paraphrasing the variable names here).

So yes: the order is absolutely guaranteed.

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