C ++错误:“获取临时数组的地址" [英] C++ error: "taking address of temporary array"

问题描述

我正在尝试在if语句中声明一个数组.我以这种方式编写了代码，以便一旦if-block退出，对象就保留在范围内，但是现在我遇到了一个新问题:获取临时数组的地址".我该如何用另一种方式重写它，以便为maskArray分配正确的值?

I am trying to declare an array inside an if-statement. I wrote my code this way so that the object stays in scope once the if-block exits, but now I have a new issue: "taking address of temporary array". How can I re-write this in an alternative way so that maskArray is assigned the correct values?

int* maskArray;
if(conditional==true)
   maskArray = (int[9]) {0,1,0,1,-4,1,0,1,0};

推荐答案

假设您以后不打算修改maskArray指向的内容，那么最好/最简单的解决方案是:

Assuming you aren't going to later modify what maskArray points to, then the best/simplest solution is:

const int* maskArray;
if(conditional==true)
{
     static const int myArray[9] = {0,1,0,1,-4,1,0,1,0};
     maskArray = &myArray[0];
}

如果您从不打算更新数组，则静态const可以工作，但是如果要更新它，则需要一个单独的副本.这可以在堆栈或堆上创建.要在堆栈上创建它:

Static const works if you never plan to update the array, but if you're going to update it, you need a separate copy. This may be created either on the stack or on the heap. To create it on the stack:

int* maskArray;
int myArray[9] = {0,1,0,1,-4,1,0,1,0};
if(conditional==true)
{
     maskArray = &myArray[0];
}
// when `myArray` goes out of scope, the pointer stored in maskArray will be useless! If a longer lifetime is needed, use the heap (see below).

要在堆上动态创建阵列的新副本，需要使用new[]分配内存.这样做的好处是，可以在决定删除它之前将其保留有效的时间.

To dynamically create new copies of the array on the heap, you need to allocate the memory using new[]. The advantage of this is that it can be kept around for as long as it's useful before you decide to delete it.

int* maskArray;
if(conditional==true)
{
     maskArray = new int[9] {0,1,0,1,-4,1,0,1,0};
}

记住要删除，稍后再使用delete[] maskArray！

Remember to delete is later using delete[] maskArray!

这篇关于C ++错误:“获取临时数组的地址"的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！