Ç - 动态内存 [英] c - dynamic memory

问题描述

大家好那里的第一个感谢你们所有的人提供帮助。
现在我想知道的双指针。我在做code是这样的：

Hi everyone out there very first thanks to all of you for providing help. Now i want to know about double pointer. I'm doing code like this:

int main()
{
    int **a;
    a = (int*)malloc(sizeof(*int)*5);
    for (i=0;i<5;i++)
    {
        a[i] = malloc(sizeof(int)*3);
    }
}

现在我不知道如果我这样做是正确的。我怎样才能把值在这种类型的数组？任何人都可以解释这个概念，例子吗？先谢谢了。

Now i dont know if I'm doing it right. How can I put values in this type of array ? Can anybody explain this concept with example ? Thanks in advance.

推荐答案

好了，你已经分配的数组大小等于：

Well, you have allocated an array equivalent in size to:

int a[5][3];

所以输入值你只是这样做：

So to enter values you just do like this:

a[0][0] = 1234;

哪个将使一个值到第一行的第一列和

Which would put a value into the first column of the first row and

a[4][2] = 9999;

将使另一个值到最后一行的最后一列。

would put another value into the last column of the last row.

由于您使用malloc，你也应该通过[I]从i = 0〜4，和免费（A []​​）循环; 然后免费（一）; 或你的程序将导致内存泄漏

Since you are using malloc, you should also loop through a[i] from i = 0 to 4, and free(a[i]); and then free(a); or your program will leak memory.

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