memcpy vs for 循环 - 从指针复制数组的正确方法是什么?

2022-01-20 00:00:00 复制 arrays pointers c++

我有一个函数 foo(int[] nums)，我理解它本质上等同于 foo(int* nums).在 foo 内部，我需要将 nums 指向的数组的内容复制到 范围内声明的一些 int[10] 中富.我理解以下内容无效:

I have a function foo(int[] nums) which I understand is essentially equivalent to foo(int* nums). Inside foo I need to copy the contents of the array pointed to by numsinto some int[10] declared within the scope of foo. I understand the following is invalid:

void foo (int[] nums) 
{
    myGlobalArray = *nums
}

复制数组的正确方法是什么?我应该像这样使用 memcpy:

What is the proper way to copy the array? Should I use memcpy like so:

void foo (int[] nums)
{
    memcpy(&myGlobalArray, nums, 10);
}

还是应该使用 for 循环?

or should I use a for loop?

void foo(int[] nums)
{
    for(int i =0; i < 10; i++)
    {
        myGlobalArray[i] = nums[i];
    }
}

我还缺少第三种选择吗?

Is there a third option that I'm missing?

推荐答案

Memcpy 可能会更快，但使用它的可能性更大.这可能取决于您的优化编译器的智能程度.

Memcpy will probably be faster, but it's more likely you will make a mistake using it. It may depend on how smart your optimizing compiler is.

您的代码不正确.应该是:

Your code is incorrect though. It should be:

memcpy(myGlobalArray, nums, 10 * sizeof(int) );

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