# 15. Complex Numbers

### Complex Type

`complex` types are used to work with complex numbers. Go has  Go two types of complex numbers, `complex64` and `complex128`

To create complex number, we use build in `complex` function.

### Declaring Complex Number

Complex numbers can be declared using any of the below way

{% code title="main.go" %}

```

var c1 complex128 = complex(2, 3)
var c2 complex64 = complex(3, 4)
var c1 = complex(2, 3)
c1 := complex(2, 3)
```

{% endcode %}

When type is not specified, complex number defaults to `complex128`

Since complex numbers must be created using `complex()` function, these do not have a corresponding zero value.

 Go provides two sizes of complex numbers, `complex64` and `complex128` . These are used to represent complex numbers.

### Declaring Complex Type

We need to use in-build `complex` function to create complex type.

{% code title="main.go" %}

```go
var x  = complex(2, 2)
var x complex128 = complex(2,2)
var y complex64 = complex(3,4)
```

{% endcode %}

If no type is specified, it defaults to `complex128`