C++ 中的 delete 操作符


delete 运算符用于释放内存。用户有权限使用此 delete 运算符释放创建的指针变量。

以下是 C++ 语言中 delete 运算符的语法:

delete pointer_variable;

以下是删除已分配内存块的语法:

delete[ ] pointer_variable;

以下是 C++ 语言中 delete 运算符的一个示例:

示例

 在线演示

#include <iostream>
using namespace std;
int main () {
   int *ptr1 = NULL;
   ptr1 = new int;
   float *ptr2 = new float(299.121);
   int *ptr3 = new int[28];
   *ptr1 = 28;
   cout << "Value of pointer variable 1 : " << *ptr1 << endl;
   cout << "Value of pointer variable 2 : " << *ptr2 << endl;
   if (!ptr3)
   cout << "Allocation of memory failed\n";
   else {
      for (int i = 10; i < 15; i++)
      ptr3[i] = i+1;
      cout << "Value of store in block of memory: ";
      for (int i = 10; i < 15; i++)
      cout << ptr3[i] << " ";
   }
   delete ptr1;
   delete ptr2;
   delete[] ptr3;
   return 0;
}

输出

Value of pointer variable 1 : 28
Value of pointer variable 2 : 299.121
Value of store in block of memory: 11 12 13 14 15

在上述程序中,声明了四个变量,其中一个是存储由 malloc 分配的内存的指针变量 *p。数组的元素由用户打印,并且打印元素的总和。要删除那些已分配的内存,请使用 delete ptr1、delete pt2 和 delete[] ptr3。

int *ptr1 = NULL;
ptr1 = new int;
float *ptr2 = new float(299.121);
int *ptr3 = new int[28];
*ptr1 = 28;
cout << "Value of pointer variable 1 : " << *ptr1 << endl;
cout << "Value of pointer variable 2 : " << *ptr2 << endl;
if (!ptr3)
cout << "Allocation of memory failed\n";
else {
   for (int i = 10; i < 15; i++)
   ptr3[i] = i+1;
   cout << "Value of store in block of memory: ";
   for (int i = 10; i < 15; i++)
   cout << ptr3[i] << " ";
}
delete ptr1;
delete ptr2;
delete[] ptr3;

更新于:26-Jun-2020

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