Applications that are free from memory leaks but perform dynamic memory allocation and deallocation frequently tend to show gradual performance degradation if they are kept running for long periods. Finally, they crash. Why is this? Recurrent allocation and deallocation of dynamic memory causes the heap to become fragmented, especially if the application allocates small memory chunks (int, an 8 byte object etc.). A fragmented heap can have many free blocks, but these blocks are small and non-contiguous. To demonstrate this, look at the following scheme that represents the system's heap. Zeros indicate free memory blocks and ones indicate memory blocks that are in use:
100101010000101010110
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