Dereferencing

Overview

Dereferencing uses the `*` operator on a pointer to access or modify the actual value stored at the memory address it points to.

Syntax

cpp

int x = 10;
int* ptr = &x;

// Dereferencing to read value
cout << *ptr; // Prints 10

// Dereferencing to write value
*ptr = 20; // Modifies x to 20

Common Pitfalls

Dereferencing a pointer that hasn't been initialized (wild pointer). It will read or overwrite random memory, causing a crash.

Interview Tips

Understand the dual use of the `*` symbol: in declarations (`int* p`), it means 'pointer to int'. In expressions (`*p = 5`), it means 'value at address'.

Real-World Example

Modifying variables indirectly via pointers.

example

cpp

#include <iostream>
using namespace std;

int main() {
    int bankBalance = 500;
    int* ptr = &bankBalance;
    
    // Modify through pointer
    *ptr += 100; // Deposits 100
    
    cout << "Balance is now: " << bankBalance << endl; // Prints 600
    return 0;
}

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