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# ft\_putnbr

**Objective:**

Create a function that displays the number entered as a parameter. The function must be able to display all possible values within an `int` type variable, including negative numbers.

***

**Turn-in Directory:**

`ex02/`

***

**Files to Turn In:**

`ft_putnbr.c`

***

**Allowed Functions:**

`write`

***

**Prototype:**

```c
void ft_putnbr(int nb);
```

***

#### **Detailed Explanation**

The `ft_putnbr` function takes an integer `nb` as input and displays it on the standard output. It handles both positive and negative numbers and uses recursion to break down the number into individual digits for printing.

***

#### **Code Implementation**

```c
void ft_putchar(char c)
{
    write(1, &c, 1);  // Write the character 'c' to the standard output
}

void ft_putnbr(int nb)
{
    long n;

    n = nb;  // Use a long variable to handle the edge case of INT_MIN
    if (n < 0)  // Handle negative numbers
    {
        ft_putchar('-');  // Print the minus sign
        n = -n;  // Convert the number to positive
    }
    if (n >= 10)  // Handle numbers with more than one digit
    {
        ft_putnbr(n / 10);  // Recursively print the digits except the last one
        n = n % 10;  // Get the last digit
    }
    if (n < 10)  // Handle single-digit numbers
    {
        ft_putchar(n + 48);  // Print the last digit (convert to ASCII)
    }
}
```

***

#### **Example Usage**

```c
#include <unistd.h>

void ft_putnbr(int nb);

int main(void)
{
    ft_putnbr(42);  // Output: 42
    ft_putnbr(-123);  // Output: -123
    ft_putnbr(0);  // Output: 0
    ft_putnbr(2147483647);  // Output: 2147483647 (INT_MAX)
    ft_putnbr(-2147483648);  // Output: -2147483648 (INT_MIN)
    return 0;
}
```

***

#### **Edge Cases to Consider**

1. **Positive Numbers**:
   * `42` → Prints `42`.
   * `2147483647` (INT\_MAX) → Prints `2147483647`.
2. **Negative Numbers**:
   * `-123` → Prints `-123`.
   * `-2147483648` (INT\_MIN) → Prints `-2147483648`.
3. **Zero**:
   * `0` → Prints `0`.
4. **Single-Digit Numbers**:
   * `5` → Prints `5`.
   * `-9` → Prints `-9`.

***

#### **Limitations of ft\_putnbr**

1. **No Bounds Checking**:
   * The function assumes the input is a valid integer. If given a non-integer input, the behavior is undefined.
2. **Recursion Depth**:
   * For very large numbers, the recursion depth may increase, but this is generally not an issue for `int` values.

***

#### **How It Works**

1. **Handle Negative Numbers**:
   * If the number is negative, print a minus sign (`-`) and convert the number to positive.
2. **Recursive Breakdown**:
   * If the number has more than one digit, recursively call `ft_putnbr` with `n / 10` to print all digits except the last one.
   * After the recursive call, print the last digit using `n % 10`.
3. **Print Single-Digit Numbers**:
   * If the number is a single digit, convert it to its ASCII representation by adding `48` (the ASCII value of `'0'`) and print it.

***

#### **Key Points to Remember**

1. **Handling INT\_MIN**:
   * The function uses a `long` variable to handle the edge case of `INT_MIN` (-2147483648), which cannot be represented as a positive `int`.
2. **Recursion**:
   * Recursion is used to break down the number into individual digits. This simplifies the logic for printing multi-digit numbers.
3. **ASCII Conversion**:
   * To print a digit, add `48` to convert it to its ASCII representation (e.g., `0` → `'0'`, `1` → `'1'`, etc.).

***

#### **Best Practices**

1. **Adhere to the Norm**:
   * Ensure your code follows the **norminette** guidelines (e.g., no more than 25 lines per function, proper indentation, etc.).
   * Run `norminette` on your file to check for compliance.
2. **Test Edge Cases**:
   * Test your function with `INT_MAX`, `INT_MIN`, `0`, and single-digit numbers.
3. **Avoid Using Library Functions**:
   * Do not use built-in functions like `printf` or `itoa` from the C standard library. The goal is to implement the functionality yourself.


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