Dynamic Memory Allocation in C++<\/h3>\n
C++ Dynamic Memory Allocation is different from that seen in the C. While C uses functions<\/strong><\/em> like malloc()<\/strong>, calloc()<\/strong>, realloc()<\/strong> and free()<\/strong> to handle operations based on DMA, C++ also uses all the 4 functions in addition to 2 different operators called new and delete<\/strong> to allocate memory dynamically.<\/p>\n These statements are indicative of the fact that DMA is implemented by the programmer itself.\u00a0C++ lacks the feature of a garbage collector which automatically helps to free up unnecessary memory space occupied by stagnant garbage values.<\/p>\n It is important to note that the memory is dynamically allocated on the Heap<\/strong>. The non-static memory and local variables get memory allocated on Stack<\/strong>.<\/em><\/p>\n Now, let us try to understand the memory map of C++<\/strong><\/p>\n From the above diagram, it is evident that there are 4 distinct regions of memory in C++.<\/p>\n 1. Program:<\/strong> This region holds the compiled code of the program. Here, all the functions of the program start at a specific address.<\/p>\n 2. Global variables:<\/strong> In this region, global variables are stored during the entire lifetime of the program.<\/p>\n 3. Stack:<\/strong> This region is responsible for storing the return addresses at function calls, arguments passed to a function as well as local variables. It is important to note that local variables remain in the computer memory as long as the function continues. Soon as the function ceases, memory is erased from the stack. In addition to all this, the stack is also responsible for storing the current state of the CPU.<\/p>\n 4. Heap:<\/strong> In this region, there is an abundance of free memory chunks that are allocated with the help of DMA.<\/p>\n Dynamic memory allocation is quite different from what the C++ compiler reserves for variables of fixed length.\u00a0The implementation of DMA proves to be pretty flexible for the programmer. The user is free to allocate and deallocate memory as and when required. Moreover, with the help of DMA, you can create\u00a0linked lists, dynamic stacks, queues, trees, etc.<\/p>\n For variables with statically allocated memory, such as int names[10], the C++ compiler reserves (4 x 10) bytes of memory which is fixed, that is, it cannot be altered. It is evident that C++ dynamic memory allocation provides immense flexibility to the user when the size of a particular variable is not known beforehand.<\/p>\n A pointer that points to the memory address of an object that has already been deleted is known as a dangling pointer in C++.<\/p>\n![\"C++](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2019\/07\/C-Memory-Map.jpg\")
<\/a><\/p>\nSignificance of Dynamic Memory Allocation in C++<\/h3>\n
Dangling Pointer in C++<\/h3>\n