# include <stdio.h>
# include <malloc.h>
void f(int ** q)
{
*q = (int *)malloc(sizeof(int)); //sizeof(数据类型) 返回值是该数据类型所占的字节数
//等价于 p = (int *)malloc(sizeof(int));
//q = 5; //error
//*q = 5; //p = 5;
**q = 5; //*p = 5;
}
int main(void)
{
int * p;
f(&p);
printf("%d\n", *p);
return 0;
}