C++ Modify Pointers - C++ Tutorial

Pointers in C++ allow direct memory access; modifying the value pointed to by a pointer also updates the original variable it references.

Changing the Value Through a Pointer

Assigning a new value to a dereferenced pointer updates the original data.

Example: Updating a Variable via a Pointer

#include <iostream>
using namespace std;

int main() {
    string motorcycleModel = "CBR600RR";  
    string* ptr = &motorcycleModel;  

    // Output original value
    cout << motorcycleModel << "\n";  

    // Output memory address
    cout << &motorcycleModel << "\n";  

    // Output value using pointer
    cout << *ptr << "\n";  

    // Modify value through pointer
    *ptr = "Ducati Panigale V4";  

    // Output updated value using pointer
    cout << *ptr << "\n";  

    // Output updated value using variable
    cout << motorcycleModel << "\n";  

    return 0;
}

C++
​x
 
#include <iostream>using namespace std;​int main() {    string motorcycleModel = "CBR600RR";      string* ptr = &motorcycleModel;  ​    // Output original value    cout << motorcycleModel << "\n";  ​    // Output memory address    cout << &motorcycleModel << "\n";  ​    // Output value using pointer    cout << *ptr << "\n";  ​    // Modify value through pointer    *ptr = "Ducati Panigale V4";  ​    // Output updated value using pointer    cout << *ptr << "\n";  ​    // Output updated value using variable    cout << motorcycleModel << "\n";  ​    return 0;}​

Output:

CBR600RR  
0x6dfed4  
CBR600RR  
Ducati Panigale V4  
Ducati Panigale V4

C++
 
CBR600RR  0x6dfed4  CBR600RR  Ducati Panigale V4  Ducati Panigale V4  ​

How It Works

The variable motorcycleModel is initially "CBR600RR".
A pointer ptr is assigned to its memory address.
*ptr retrieves the original value ("CBR600RR").
Modifying *ptr updates motorcycleModel, replacing "CBR600RR" with "Ducati Panigale V4".
Both *ptr and motorcycleModel now reflect the new value.