1. Variable
2. Constant Variable
3. Multi-line Strings
4. Double
5. Boolean
6. String Interpolation
7. Type Annotations
8. Type Inference
9. Description of Data Types

var ⇒ variable data can be changed

let ⇒ variable data is constant

1. variable ⇒ var str = “Hello World!’ (It can be changed later)

2. Constant Variable

values set once and can’t be changed.

let name = "Zeeshan"
name = "Ali"

print(name)

output

it will give out an error because let variables can’t be changed