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Life is like a flash of time, love and hate can become mist and clouds, fame and fortune will eventually be like dirt, only time cannot be let down.

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1. The basics of new operations

In software development projects, we often need to dynamically allocate and free memory space. In C language, we use malloc and free.

Simpler operators new and delete are provided in C++.

Example of new operator

new int ; // Create a storage space for storing integers and return an address pointing to the storage space
 new int(100);
 new int [3][6]; //Open a storage space for storing two-dimensional arrays and return the address of the first element

The format of the new operator:new type [initial value]

The initial value cannot be specified when allocating array space with new. If the allocation fails due to insufficient memory or other reasons, a NULL pointer is returned.

delete operator format:delete[ ] pointer variable

float *p = new float(3.14);
 delete p;
 new char[10];
 delete[] pt; //Add [] in front of the pointer to indicate the operation of array space

2. New operator dynamically creates objects

//Define class Box
 Box *pt; //Define the value of a pointer to a new object
 pt = new Box; //Storing the starting address of the newly created object in pt
 //You can access this address in the program
 cout <<p->height; //The height member of the output object
 cout<<p->volume();//Output object member function

At the same time, when executing new, initial value is also allowed

Box* pt = new Box(12,12,12);

When new fails to open up space, the return value is 0.

When you don't need to use new to create objects, you can use delete to delete.

detele pt; //Release the memory space pointed to by pt

When pointing to the delete operator, the destructor is automatically called before the memory is freed.