Question

据我了解，您可以使用相同的变量名重新分配堆，它将在空间的不同位置分配内存。

但是，在此示例中，我在第二个malloc中为指针变量x获得了相同的内存地址。有什么想法吗？

void main()
{
    int *x = (int*)malloc(sizeof(int)); //allocate space for int value
    *x = 100;   //dereference x for value
    printf("The value of x is %i address is %p\n",*x, &x);

    int *y = (int*)malloc(sizeof(int)); //allocate space for int value
    *y = 150;   //dereference x for value
    printf("The value of y is %i address is %p\n",*y, &y); 

    x = (int*)malloc(sizeof(int));  //allocate space for int value
    *x = 400;   //dereference x for value
    printf("The value of x is %i address is %p\n",*x, &x);
}

gcc给我这个：

The value of x is 100 address is 0xffffcc08
The value of y is 150 address is 0xffffcc00
The value of x is 400 address is 0xffffcc08

Answer 1

printf("The value of x is %i address is %p\n",*x, &x);

&x在这里给出变量x的地址，而不是变量所指向的地址。要获取其指向的地址，请使用以下命令：

printf("The value of x is %i address is %p\n",*x, (void *)x)

C中的堆分配

1 个答案: