用new動態分配存儲空間
用法1: P = new T; P是 T*的指針,開闢也給大小爲sizeof(T)的內存,並將起始地址賦給P;
或者int *p= new int;
用法2: P = new T[N]; P是 T*的指針,開闢也給大小爲sizeof(T)*N 的內存,並將起始地址賦給P;
int i=5;
int * p= new int [i*20];
用delete釋放動態分配的內存
delete 指針;//該指針必須是動態分配的空間。
int *p= new int;
*p = 5;
delete p;//只能被釋放一次
如果p指向的是動態分配的數組,delete時要加"[ ]"
delete [ ] 指針;
int *p = new int [20];
delete [ ] p;