# Swift - fdim() Function

The Swift fdim() function returns positive difference between x and y, if x > y, else returns zero. Mathematically, it can be expressed as:

fdim (x, y) = max (x-y, 0)

### Syntax

In Foundation framework, it is defined as follows:

```public func fdim(_ lhs: CGFloat, _ rhs: CGFloat) -> CGFloat
public func fdim(_ lhs: Float, _ rhs: Float) -> Float
public func fdim(_ lhs: Float80, _ rhs: Float80) -> Float80
public func fdim(_ __x: Double, _ __y: Double) -> Double
```

### Parameters

 `x, lhs` Specify the first value. `y, rhs` Specify the second value.

### Return Value

Returns the positive difference between x and y.

### Example:

The example below shows the usage of fdim() function.

```import Foundation

print("fdim(100.0, 50.0) = \(fdim(100.0, 50.0))")
print("fdim(50.0, -100.0) = \(fdim(50.0, -100.0))")
print("fdim(-50.0, 50.0) = \(fdim(-50.0, 50.0))")
print("fdim(-100.0, -50.0) = \(fdim(-100.0, -50.0))")
```

The output of the above code will be:

```fdim(100.0, 50.0) = 50.0
fdim(50.0, -100.0) = 150.0
fdim(-50.0, 50.0) = 0.0
fdim(-100.0, -50.0) = 0.0
```

❮ Swift Math Functions

5