C++ 将动态数组初始化为 0？
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initializing a dynamic array to 0?
提问by Luchian Grigore
int main()
{
int arraySize;
int arrayMain[arraySize-1];
cout << "\n\nEnter Total Number of Elements in Array.\n\n";
cin >> arraySize;
arrayMain[arraySize-1]={0};
cout <<"\n\n" <<arrayMain;
return 0;
}
my compiler freezes when I compile the above code. I am confused on how to set a dynamic array to 0?
当我编译上面的代码时，我的编译器冻结了。我对如何将动态数组设置为 0 感到困惑？
回答by Luchian Grigore
You use a std::vector:
你使用一个std::vector：
std::vector<int> vec(arraySize-1);
Your code is invalid because 1) arraySizeisn't initialized and 2) you can't have variable length arrays in C++. So either use a vector or allocate the memory dynamically (which is what std::vectordoes internally):
您的代码无效，因为 1)arraySize未初始化和 2) 在 C++ 中不能有可变长度数组。因此，要么使用向量，要么动态分配内存（这是std::vector内部执行的操作）：
int* arrayMain = new int[arraySize-1] ();
Note the ()at the end - it's used to value-initialize the elements, so the array will have its elements set to 0.
请注意()末尾的 - 它用于对元素进行值初始化，因此数组的元素将设置为 0。
回答by Jaydip Pansuriya
if you want to initialize whole array to zero do this ,
如果要将整个数组初始化为零，请执行此操作，
int *p = new int[n]{0};
回答by hmjd
If you must use a dynamic array you can use value initialization (though std::vector<int>would be the recommended solution):
如果您必须使用动态数组，您可以使用值初始化（尽管std::vector<int>这是推荐的解决方案）：
int* arrayMain = new int[arraySize - 1]();
Check the result of input operation to ensure the variable has been assigned a correct value:
检查输入操作的结果以确保变量已分配正确的值：
if (cin >> arraySize && arraySize > 1) // > 1 to allocate an array with at least
{ // one element (unsure why the '-1').
int* arrayMain = new int[arraySize - 1]();
// Delete 'arrayMain' when no longer required.
delete[] arrayMain;
}
Note the use of cout:
注意使用cout：
cout <<"\n\n" <<arrayMain;
will print the address of the arrayMainarray, not each individual element. To print each individual you need index each element in turn:
将打印arrayMain数组的地址，而不是每个单独的元素。要打印每个人，您需要依次索引每个元素：
for (int i = 0; i < arraySize - 1; i++) std::cout << arrayMain[i] << '\n';
