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Constants, static variables and global variables are allocated in the program's data segment at compile time. Local variables are allocated on the stack at runtime. Variables cannot be allocated on the heap, you must use a constant, static variable, global variable or local variable to store the start address of a dynamic memory allocation. The variable must be a raw pointer or a reference handle (a smart pointer).
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Is memory allocated at runtime for the static variables?
No. Static memory is allocated at compile time. Static variables are allocated within the program's data segment which is a physical part of the executable. When you load the executable into memory, the operating system sets aside enough memory for the entire executable and copies it, byte for byte, into that memory. So when the program is executed, the data segment is already allocated.
Difference between dynamic and static memory allocation?
Static memory allocation is memory allocated on the "stack" and cannot be resized after the initial allocation, while dynamic memory allocation is memory allocated in the "heap", and can be dynamically expanded and shrunk as necessary.
What is the difference between stack and heap memory in C?
stack is memory allocated for temporary variables used by subroutinesheap is memory allocated for long term data structures (e.g. linked lists, trees) that are likely to change sizeBoth are forms of dynamically allocated memory (i.e. allocated/deallocated at runtime as needed), but the allocation/deallocation method and their place in physical/virtual memory are differentStatically allocated memory (i.e. allocated at compile/link time) is used for variables and data structures that must exist as long as the program is running and cannot change in size while the program is running.
Where the Memory is allocated for a variable in a program?
if a variable is of value type memory is allocated on stack memory.. if it is of reference type,memory is allocated on heap memory..
Why memory is divided into initialized and uninitialized areas?
The program's data segment. This area of memory is allocated by the linker and is used to store the program's global variables, static variables, static arrays and constants. Constants are always initialised, as are static variables, but global variables and static arrays need not be initialised.
Where dynamic variables are stored?
Dynamic variables are stored in a memory heap allocated to them at run time.
Is memory allocated at runtime for the static variables?
No. Static memory is allocated at compile time. Static variables are allocated within the program's data segment which is a physical part of the executable. When you load the executable into memory, the operating system sets aside enough memory for the entire executable and copies it, byte for byte, into that memory. So when the program is executed, the data segment is already allocated.
Difference between dynamic and static memory allocation?
Static memory allocation is memory allocated on the "stack" and cannot be resized after the initial allocation, while dynamic memory allocation is memory allocated in the "heap", and can be dynamically expanded and shrunk as necessary.
What is the difference between stack and heap memory in C?
stack is memory allocated for temporary variables used by subroutinesheap is memory allocated for long term data structures (e.g. linked lists, trees) that are likely to change sizeBoth are forms of dynamically allocated memory (i.e. allocated/deallocated at runtime as needed), but the allocation/deallocation method and their place in physical/virtual memory are differentStatically allocated memory (i.e. allocated at compile/link time) is used for variables and data structures that must exist as long as the program is running and cannot change in size while the program is running.
Where the Memory is allocated for a variable in a program?
if a variable is of value type memory is allocated on stack memory.. if it is of reference type,memory is allocated on heap memory..
What is a stack Is it a part of RAM?
The satck is a piece of memory that is allocated on the RAM, that a thread of a computer program uses for most of its variables.
Why memory is divided into initialized and uninitialized areas?
The program's data segment. This area of memory is allocated by the linker and is used to store the program's global variables, static variables, static arrays and constants. Constants are always initialised, as are static variables, but global variables and static arrays need not be initialised.
C memory model?
Memory Organization for a process -------------------------------------------- CODE SEGMENT: contains executable code DATASEGMENT:contains static and global variable HEAP SEGMENT:Dynamically allocated variables will be in heap STACK SEGMENT:For local or automatic variables PREM G premgnath@gmail.com
What is the difference between static and dynamic memory?
There is no such thing as dynamic memory, but we often use the term to mean non-static memory. Static memory is where all constant variables, global variables and static variables are allocated in static memory. Static memory is a contiguous block of memory of fixed length divided into two sections: initialised memory and uninitialised memory. Initialised variables and constants are allocated to the initialised section and are stored as a bitmap image in the executable itself. Uninitialised variables are allocated in the uninitialised section which is typically a block of zero-initialised memory. No bitmap image is required for uninitialised memory, only its length need be stored in the executable. The compiler can determine the amount of memory required for each constant and variable. Non-static memory is essentially all other memory used by a program. Every thread has its own call stack allocated as each thread is instantiated and released as each thread is destroyed. All stacks are fixed-length (determined at design time). The call stack is used to store local variables, automatic variables and temporary variables, as well as to implement exception handling. The heap (or free store) is essentially all other memory available to the program and is used to instantiate all anonymous variables. The heap is what we generally mean by dynamic memory because anonymous variables are created and destroyed as and when they are required at runtime. Since we cannot refer to an anonymous variable by name (being anonymous means they have no name), we must refer to them solely by their address. This means we must use pointer variables to store those addresses. If we have a large number of anonymous variables of the same type to keep track of, then we typically allocate them in contiguous memory and maintain a single pointer to the start of the allocation. This single pointer allows us to access the memory just as we would a built-in array. We also need to keep track of how many variables (elements) are allocated in the array to avoid buffer overruns. This allows us to easily allocate and release any number of anonymous variables at runtime. However, in C++ we rarely use "dynamic memory" directly. Although necessary in C Programming, C++ programmers prefer to use resource handles or "smart" pointers instead. In this way the language itself handles the underlying memory allocations for us, ensuring that memory is allocated and released in a timely manner, and thus minimising the risk of creating resource leaks -- a common problem with low-level C programming. The C++ std::vector is an example of a resource handle and most non-trivial C++ programs will include one or more std::vector<std::unique_ptr<T>> variables to keep track of any number of pointers to type T objects.
In what are various cells of memory allocated consecutively?
Contiguous memory address are allocated to an array or vector.
How system knows what range of memory it has allocated while using free?
use free() how does the system know what range of memory it has allocated use free() how does the system know what range of memory it has allocated
What do you mean by free store in c plus plus?
The free store in any language refers to the heap. The three main areas of memory that all C++ programs use are the heap, the call stack and static memory. Static memory is allocated at compile time, is fixed-length and caters for all static variables, global variables and constant variables. Call stacks are also fixed-length and are allocated to threads of execution as they are instantiated (each thread has its own stack). The free store or heap is essentially all remaining memory accessible to our program. To use the heap we must request memory from the system as it is required and release it when we are finished with it.
