有动态的和静态的 new/deletemalloc/free例如：分配内存 int **a = new int* [lenth]; for(int i = 0; i < lenth; ++i) a[i] = new int [lenth]; 释掘或改放判判内存：团返 for(int i = 0; i < lenth; ++i) delete []a[i]; delete []a;
