YouTipSwift Repeat While Loop
# Swift repeat...while Loop
[Swift Loops](#)
Unlike for and while loops, which evaluate the condition statement before executing the loop body, the Swift repeat...while loop checks the condition at the end of the loop execution.
### Syntax
The syntax format of the Swift repeat...while loop is as follows:
```swift
repeat {
statement(s);
}while( condition );
Please note that the conditional expression appears at the end of the loop, so the statement(s) in the loop will be executed at least once before the condition is tested.
If the condition is true, the control flow jumps back to repeat, and then re-executes the statement(s) in the loop. This process repeats continuously until the given condition becomes false.
The number 0, the string '0' and "", an empty list(), and undefined variables are all **false**, while everything else is **true**. true is negated using the **!** sign or **not**, and returns false after negation.
**Flowchart:**
!(#)
### Example
```swift
import Cocoa
var index = 15
repeat{
print( "index value is (index)")
index = index + 1
}while index < 20
The output of the above program execution is:
```text
index value is 15
index value is 16
index value is 17
index value is 18
index value is 19
[Swift Loops](#)