The **`creall` function** is part of the `<tgmath.h>` header file in C. 

It is used to return the real part of a complex number of type `long double`. The function takes in a single parameter: a `long double complex` number. 

> A complex number has a **real** and an **imaginary** part.

The illustration below shows how `creall` works:

## Declaration

The `creall` function is defined as follows:

```C
long double creall(long double complex z);
```
It takes in a single parameter of type `long double complex`.

### Example

The following code snippet shows how we can use the `creall` function. The code below outputs the real part of the complex number:

#include <stdio.h> // Including header file for printf function
#include <tgmath.h> // Including header file for creall function

int main(){

  long double complex z = 7.0 + 3.0*I; // assign value to variable
  printf("The real part is %Lf", creall(z));
  return 0;
}

> `creall`, `creal` and `crealf` are similar functions.

* `creall` takes a `long double` complex number and returns its `long double` real
* `creal` takes a `double` complex number and returns its `double` real
* `crealf` takes a `float` complex number and returns its`float` real

What is creall in C?

Declaration

Example