动态数组是否在内存中连续分配？

Question

int* arr = new int[5];

Are the values of the array pointed by arr allocated contiguously in the heap?

Thanks.

Answer 1

The right syntax for a dynamic array is int* arr = new int[5]; . Yes, it will be allocated contiguously.

This is not a recommended way of using an array. If you know array size at compile time and it is not too large, make it local: int arr[5]; or std::array<int,5> arr; . Otherwise, use std::vector<int> arr(5); . new should be rarely used in modern C++.

Edit: Genuine multi-dimensional dynamic arrays allocated like these

int (*arr2)[6] = new int[5][6];
int (*arr3)[6][7] = new int[5][6][7];

are also contiguous. But if you use a 1D array of pointers and allocate dynamic array to each pointer:

int** arrp = new int*[5];
for(int i=0; i<5; i++)
    arrp[i] = new int[6]; 

then data in arrp is not contiguous, even though you can use it the same way as arr2 , eg:

arrp[2][3] = 4