---
title: 6.15 Recursive Functions
description: A recursive function is a function that calls itself during its execution. Recursion allows a problem to be divided into smaller instances of the same problem until a condition is reached that stops further recursive calls. A recursive function requires…
url: "https://edcret.in/docs/cpp-programming/functions/6-15-recursive-functions/"
updated: "2026-09-06"
category: C++ Programming / Functions
---

# 6.15 Recursive Functions

A recursive function is a function that calls itself during its execution. Recursion allows a problem to be divided into smaller instances of the same problem until a condition is reached that stops further recursive calls.

A recursive function requires a **base case** to terminate the recursion. Without an appropriate base case, the function continues calling itself until the available call stack is exhausted.

## Source Code

```
#include <iostream>

int factorial(int number)
{
    if (number <= 1)
    {
        return 1;
    }

    return number * factorial(number - 1);
}

int main()
{
    int result = factorial(5);

    std::cout << "Factorial: " << result << '\n';

    return 0;
}
```

## Output

```
Factorial: 120
```

## Explanation

- `factorial()` is a recursive function because it calls itself.
- The condition `number <= 1` is the **base case** that terminates the recursion.
- When the base case is reached, the function returns `1` without making another recursive call.
- `factorial(number - 1)` creates a recursive call using a smaller value of `number`.
- For `factorial(5)`, the recursive calls proceed as:`factorial(5) factorial(4) factorial(3) factorial(2) factorial(1)`
- `factorial(1)` reaches the base case and returns `1`.
- The pending function calls then return their results:`5 × 4 × 3 × 2 × 1 = 120`
- Each recursive call requires additional stack storage until that call returns.
- A recursive function must have a terminating condition to prevent unbounded recursion.
- `return 0;` terminates the program successfully.