Why Should We Call `delete` in C Before Program Exit?

Why Call Delete in C Before Program Exit?

In C , it's essential to explicitly call delete for heap-allocated memory before program termination. Failure to do so can result in memory leaks and unreliable application behavior.

Memory Deallocation at Program Exit

While most operating systems automatically reclaim heap memory when a program exits, relying solely on this default behavior can be problematic. There are two key reasons for this:

Destructor Execution:
Heap-allocated objects in C have destructors that are intended to perform cleanup actions like closing files, releasing resources, or logging information. If the operating system deallocates memory without invoking destructors, these critical actions will not occur.

Good Programming Practice:
Explicitly calling delete serves as a clear indication that the corresponding allocation is no longer needed, making it easier for other developers reading the code to understand the memory management logic. It also eliminates any confusion about whether memory is being properly released.

Example:

Consider the following code snippet:

int main() {
    A* a = new A();
    a->DoSomething();
    return 0;  // Program exits without calling delete a
}

In this example, the memory allocated for object a won't be freed upon program exit, resulting in a memory leak.

Conclusion:

It is always advisable to explicitly call delete for heap-allocated memory in C , even if it's expected that memory will be deallocated automatically by the operating system. This ensures correct destructor execution and promotes good programming practices.

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