Summary of static memory allocation and dynamic memory allocation

Static memory is automatically allocated by the system , Automatically released by the system . Static memory is allocated in the stack , If main Function calls another function , Then press the called function onto a stack . To execute the called function is to make all the memory space allocated by the system for this function out of the stack one by one . The end of the stack is the completion of the execution of the called function .

The order of the stack is "first in, then out" , That is, the post execution of the advanced stack , Because the advanced stack is pressed down , So the execution is always the content at the top of the stack . The completion of program execution means “ All the contents in the stack are out of the stack ”. Out of the stack is “ Release ”. When the top of the stack is all out of the stack, it will become the top of the stack , Then continue to execute the stack contents , Keep going out of the stack . The complete execution of the whole program means “ All memory space allocated by the system is out of the stack ”, All memory has been released . Therefore, the memory space allocated by the system for static variables will be released after the execution of the program .

Dynamic memory is released manually by the programmer , Function termination is not automatically released by the system . This shows that he is definitely not allocated in the stack . Where did he distribute it ？ Is in “ In the pile ” The distribution of , Stack is a storage structure , Heap is not a storage structure , Heap is a sort of memory allocation . Also said , Dynamic memory is allocated by heap sorting . Previously, I talked about sorting , Sort like bubbling , Insertion sort , Selection sort , Quick sort . Heap sorting is also a sort method , Because dynamic memory is allocated in the heap , It is allocated in a sort way , Not in the stack , So the function will not be released after running .

Because dynamic memory is allocated manually by the programmer , Hand release , So there will be a serious problem at this time ： If you forget to release , Will cause memory leaks , So dynamic memory allocation has advantages , There are also shortcomings. . The use of dynamic memory is very flexible , But there are many problems that need attention .

Memory allocation is a very complicated problem . Now it's just getting started , So don't talk too much .