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Questions and Answers
What does a pointer variable store?
What does a pointer variable store?
Which operator is used to get the memory address of a variable?
Which operator is used to get the memory address of a variable?
What is meant by 'dereferencing' a pointer?
What is meant by 'dereferencing' a pointer?
Given int x = 20; int* ptr = &x;, what does ptr hold?
Given int x = 20; int* ptr = &x;, what does ptr hold?
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What is the correct syntax for declaring a pointer to a character variable?
What is the correct syntax for declaring a pointer to a character variable?
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Flashcards
Pointer
Pointer
A special variable that stores the memory address of another variable in C++.
What is a memory address?
What is a memory address?
Every location in the computer's memory has a unique address. Pointers store these addresses.
Declaring a Pointer
Declaring a Pointer
To create a pointer variable, you use the * symbol before the variable name.
Assigning a Value to a Pointer
Assigning a Value to a Pointer
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Dereferencing a Pointer
Dereferencing a Pointer
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Study Notes
Pointers
- Pointers in C++ are special variables that store memory addresses of other variables. They are powerful but require careful use.
- Memory addresses uniquely identify each location in a computer's memory where a variable is stored.
- A pointer holds a memory address, not the variable's value itself.
- Declaring a pointer:
int* ptr;//ptris a pointer to an integer
Assigning Values to Pointers
- Use the
&operator to get a variable's memory address:int x = 10; int* ptr = &x; ptrnow holds the address ofx.
Dereferencing a Pointer
- Use the
*operator to access or modify the value at the address stored in the pointer:cout << *ptr;// Prints the value ofx(10). *ptr = 20;// Changes the value ofxto 20.
Null Pointer
- A pointer can be initialized to
nullptrto indicate it doesn't point to a valid memory location:int* ptr = nullptr;
Void Pointers
- A void pointer can store the address of any data type.
- Its type is
void*.
Double Pointers
- A double pointer holds the address of a pointer.
- Example:
type** ptr;
Pointer Arithmetic
- Adding or subtracting integers to a pointer manipulates its memory address (e.g.,
pa = pa + 5). The size of the data being pointed to is a factor. - A pointer can be compared to another using operators like
==,!=,>,<.
Pointers and Arrays
- The name of an array (without subscripts) is a pointer to the first element in the array:
int arr[10]; int* ptr = arr;
Dynamic Memory Allocation
- Dynamically allocating memory lets you set aside memory at runtime.
- Use
newto allocate memory (e.g.,int* arr = new int[n];). - Release memory when it is no longer needed using the
delete[]operator:delete[] arr;to avoid memory leaks.
Array of Pointers
- An array can contain pointers as its elements.
Passing Arrays to Functions
- When an array is passed to a function, the function receives a pointer to the first element of the array. This allows changes to the array to be reflected in the calling function.
References and Pointers
- Call-by-value methods copy the variable's value, call-by-reference methods pass the variable's address.
- Pass-by-reference with a pointer, or reference, permits changing the original variable within the function.
String Pointers
- String variables have memory locations.
- The address can be found using the
&operator.
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Description
This quiz covers the fundamentals of pointers in C++, including their declaration, assignment, and dereferencing. It also explores concepts such as null pointers and void pointers, ensuring a comprehensive understanding of how pointers work in memory management.
