---
title: 6.11 Passing by Pointer
description: Passing by pointer allows a function to receive the address of an object through a pointer parameter. The function can then use the pointer to access or modify the original object. Unlike a reference parameter, a pointer parameter can also…
url: "https://magenta-tarsier-454184.hostingersite.com/docs/cpp-programming/functions/6-11-passing-by-pointer/"
updated: "2026-09-06"
category: C++ Programming / Functions
---

# 6.11 Passing by Pointer

Passing by pointer allows a function to receive the address of an object through a pointer parameter. The function can then use the pointer to access or modify the original object.

Unlike a reference parameter, a pointer parameter can also represent a null pointer, allowing the function to determine whether a valid object was supplied.

## Source Code

```
#include <iostream>

void updateValue(int* value)
{
    *value = 100;
}

int main()
{
    int number = 50;

    updateValue(&number);

    std::cout << "Number: " << number << 'n';

    return 0;
}
```

## Output

```
Number: 100
```

## Explanation

- `int* value` declares `value` as a pointer parameter that can store the address of an `int` object.
- `&number` obtains the memory address of the variable `number`.
- `updateValue(&number)` passes that address to the function.
- `value` therefore points to the original `number` object.
- The dereference operator (`*`) accesses the object stored at the address held by `value`.
- `*value = 100;` modifies the original `number` variable through the pointer.
- After the function returns, `number` contains `100`.
- Unlike a reference, a pointer can be assigned `nullptr` to represent the absence of an object.
- A pointer should be dereferenced only when it points to a valid object.