A pointer stores a memory address; declare with and dereference to access value, e.g., int x = 10; int ptr = &x; links ptr to x’s address.
Using pointers correctly in C involves understanding memory management, avoiding common pitfalls, and following best practices. Pointers are powerful but require careful handling to prevent crashes, memory leaks, or undefined behavior.
Understand What a Pointer Is
A pointer is a variable that stores the memory address of another variable. You declare it using the * symbol and access the value at that address using dereferencing.
Example:
int x = 10;
int* ptr = &x; // ptr holds the address of x
cout
Always initialize pointers. Uninitialized (wild) pointers can point to random memory locations.
Prefer initializing to nullptr if you don’t have a valid address yet:
int* ptr = nullptr;
Manage Dynamic Memory Carefully
Use new to allocate memory on the heap and delete to free it. For arrays, use new[] and delete[].
int* arr = new int[5];
// ... use arr ...
delete[] arr; // Must match new[] with delete[]
arr = nullptr; // Prevent dangling pointer
Forgetting to call delete leads to memory leaks. Calling delete twice causes undefined behavior.
Smart pointers like std::unique_ptr and std::shared_ptr automate memory management and are safer than raw pointers.
Example:
#include A dangling pointer points to memory that has already been freed. After calling delete, set the pointer to nullptr to avoid accidental use. Dereferencing a null pointer causes a crash. Always check before using:
if (ptr != nullptr) { Modern C often avoids raw pointers for owning memory. Use smart pointers or references instead. If you don’t need to reseat (change the address), prefer references over pointers. They’re safer and cleaner.
void increment(int& ref) { References can’t be null and must be initialized, reducing errors. Basically, use pointers only when necessary—like for dynamic allocation, polymorphism, or interfacing with C APIs. Otherwise, lean on modern C features like smart pointers and references. Safety and clarity come first.
std::unique_ptr
cout Avoid Dangling and Null Pointers
??cout
}
Use References When Possible
?? ref;
}
// Called as: increment(x);
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