Problems with dynamic memory allocation (memory hole)------C + + programming principles and Practices (advanced)

Where is the question of new? In fact, the problem is with the combination of new and delete. Examine the memory allocation and release process in the following program:

while (1) {    big* p=new Big;
//......    small* n1=new Small;
//......    Delete p;    small* n2=new Small;
//......}

In each loop step, we created two small, during which we also allocated a big and then released it. Looking at this code, we may expect to "consume" 2*sizeof (Small) bytes of memory (plus the additional overhead of dynamic memory allocation) each time we perform a looping step. In practice, however, each cycle step consumes more memory.

As you can see, there is some unused space ("holes") left in dynamic memory for Each loop step. These voids can be just a few bytes in size, but if we can't use them effectively, the damage is the same as a memory leak. In memory, the free space is dispersed, creating a lot of small "holes" that cannot meet new memory requirements, called memory fragmentation. The memory management program will eventually run out of "holes" that are large enough to leave only small holes that cannot be used. This is a serious problem that can occur with any system that uses new and delete frequently after a long run.

Problems with dynamic memory allocation (memory hole)------C + + programming principles and Practices (advanced)