When Should I Use the `new` Keyword in C ?

Understanding the Need for the 'new' Keyword in C

C introduces the 'new' keyword for memory management, offering control over object creation and allocation. To understand its usage, let's explore two methods:

Method 1: Using 'new'

Using 'new' allocates memory for an object on the free store (heap), which provides the following:

• Explicit deletion is required to release the allocated memory and prevent memory leaks.
• Objects remain allocated until explicitly deleted, enabling data persistence even beyond their scope.

MyClass* myClass = new MyClass();
myClass->MyField = "Hello world!";

Method 2: Without 'new'

Declaring an object without 'new' allocates it on the stack, which is temporary storage for local variables. This approach has the following characteristics:

• Memory allocation is implicit and occurs automatically.
• Deletion is unnecessary since memory is reclaimed when an object goes out of scope.

MyClass myClass;
myClass.MyField = "Hello world!";

Choosing the Right Method

The choice depends on the desired memory management and object durability requirements.

• Use 'new' if:

  • You want to dynamically allocate an object and control its lifetime.
  • You need to return a pointer to an object from a function (returning an object allocated on the stack is unsafe).

• Avoid 'new' if:

  • You prefer automatic memory management without risking memory leaks.
  • You do not need object persistence beyond its scope.

Rule of Thumb for Memory Management:

To prevent memory leaks, adopt the practice of pairing every 'new' with a 'delete' statement. This ensures proper memory cleanup and avoids potential issues.

Foobar *foobar = new Foobar();
// ...
delete foobar; // Cleanup the allocated memory

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