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Questions and Answers
What does a pointer in C++ store?
What does a pointer in C++ store?
Which operator is used to deallocate dynamic memory in C++?
Which operator is used to deallocate dynamic memory in C++?
What kind of memory does the heap refer to in C++?
What kind of memory does the heap refer to in C++?
How do you access the value pointed to by a pointer in C++?
How do you access the value pointed to by a pointer in C++?
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What is a key advantage of using pointers?
What is a key advantage of using pointers?
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What should a pointer be initialized to if it does not yet point to a valid memory address?
What should a pointer be initialized to if it does not yet point to a valid memory address?
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Which of the following statements about stack memory is accurate?
Which of the following statements about stack memory is accurate?
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What occurs when you allocate dynamic memory using the new operator?
What occurs when you allocate dynamic memory using the new operator?
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What is a downside of using pointers for memory allocation?
What is a downside of using pointers for memory allocation?
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Which statement best describes shallow copies in the context of pointers?
Which statement best describes shallow copies in the context of pointers?
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What is the main requirement for static arrays regarding their size?
What is the main requirement for static arrays regarding their size?
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How do you access a particular index of an array using a pointer?
How do you access a particular index of an array using a pointer?
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What happens when memory allocated dynamically is no longer required?
What happens when memory allocated dynamically is no longer required?
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Which operator is used to deallocate memory for an entire array?
Which operator is used to deallocate memory for an entire array?
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What is a shallow copy?
What is a shallow copy?
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What is the difference between shallow copy and deep copy?
What is the difference between shallow copy and deep copy?
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What is the correct syntax for using the std::copy function?
What is the correct syntax for using the std::copy function?
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What does a deep copy algorithm typically involve?
What does a deep copy algorithm typically involve?
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When dereferencing a pointer to access an object's member functions, what operator is used?
When dereferencing a pointer to access an object's member functions, what operator is used?
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Which of the following statements is true regarding pointer arithmetic?
Which of the following statements is true regarding pointer arithmetic?
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Study Notes
CSC 1061: Pointers and Dynamic Memory
- Objectives: Trace code with simple pointers, use pointer variables with C++ new operator to allocate single dynamic variables and arrays, use the C++ delete operator to release dynamic variables/arrays, follow pointer and array behavior as parameters.
Agenda: Week 07
- Pointers: Topics include pointer to single memory, stack and heap memory, dynamic memory, pointer to array of memory, pointer to objects, shallow and deep copies.
Why Pointers?
- Pointers allow developers to manage dynamic (runtime) memory on the heap.
- Spiderman quote: "With great power comes great responsibility."
Pointer Terminology and Syntax
-
Declare a pointer:
dataType *ptrName; -
Initialize a pointer:
ptrName = nullptr; -
Address of a variable:
&variable -
Contents of a variable (dereferencing):
*ptrName -
Allocate dynamic heap memory:
new -
Deallocate dynamic heap memory:
delete
Pointers
- A pointer stores the memory address, not the value itself.
- Pointers can control both stack and heap memory.
- Stack memory is compiler-managed (compile-time).
- Heap memory is developer-managed (runtime) allocated using
newand deallocated usingdelete.
Pointer Example
- In C++, pointers store the memory addresses of other variables.
- Important to understand who is managing memory (the developer or the compiler) and where (stack or heap)
Pointer: Dereferencing Operator
- Pointers used by using dereferencing operator (
*) . - It accesses the value pointed to.
Allocation of Memory: Heap
- C++ allows memory allocation for variables or arrays at runtime using
new. - Dynamic memory using operator
new. - A pointer to the beginning of the allocated memory block is returned.
- The size of the array using
newcannot be a variable (it must be a constant unlike static arrays).
Pointer Accessing Array Elements
- Subscript [] operator directly dereferences to get value of an element.
- Use
ptr[index]instead of*ptr + i.
Deallocation of Memory: Heap
- Memory allocated dynamically is not needed for the entire program.
- Memory is freed using delete[] operator.
- Important to
delete []allocated arrays to prevent memory leaks.
Objects and Pointers
- Pointers to objects must dereference using the arrow operator (
->) first before calling member functions.
Shallow Copy
- Two or more pointers can control the same memory address.
- Copying a pointer makes a copy of the pointer, not the memory it points to.
Deep Copy
- To copy dynamic memory, new memory is allocated, and the values from the original pointer are copied to the new memory.
STD::COPY(FIRST, LAST, DESTINATION)
- Built-in function in
<algorithm>to copy element ranges. - Linear in the distance.
- First pointer is inclusive, last is exclusive.
Deep Copy: Dynamic Memory Algorithm
- Create a temporary pointer and allocate memory (same or bigger size).
- Copy memory from original pointer to the new pointer.
- Deallocate original pointer memory.
- Assign the original pointer to the new one.
Review Check
- Complete the 1.9.4 Pointers tutorial with all activities.
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Description
This quiz covers the fundamental concepts of pointers and dynamic memory management in C++. Participants will learn how to declare and initialize pointers, allocate and deallocate dynamic memory, and understand the behavior of pointers with arrays and objects. Get ready to test your knowledge on this essential aspect of programming!
