Swift - Loops

In Swift, loops are a fundamental control flow mechanism that allows you to execute a block of code multiple times. Here's an overview of the types of loops in Swift:

1. For-In Loop

The for-in loop iterates over a sequence, such as items in an array, a range of numbers, or characters in a string.

Iterating over a range:

for index in 1...5 {
    print("\(index) times 5 is \(index * 5)")
}

Iterating over an array:

let names = ["Anna", "Alex", "Brian", "Jack"]
for name in names {
    print("Hello, \(name)!")
}

Iterating over a dictionary:

let numberSymbols: [Int: String] = [1: "One", 2: "Two", 3: "Three"]
for (number, symbol) in numberSymbols {
    print("The symbol for \(number) is \(symbol)")
}

2. While Loop

The while loop evaluates a condition and runs a block of code as long as the condition is true.

var count = 0
while count < 5 {
    print("Count is \(count)")
    count += 1
}

3. Repeat-While Loop

The repeat-while loop is similar to the while loop but checks the condition after the code has run, ensuring the loop runs at least once.

var number = 0
repeat {
    print("Number is \(number)")
    number += 1
} while number < 5

4. Control Transfer Statements

While working with loops, you often need control transfer statements to modify the execution flow:

continue: The continue statement tells the loop to stop the current iteration and start the next one.

for num in 1...10 {
    if num % 2 == 0 {
        continue
    }
    print(num)  // This will print only odd numbers.
}

break: The break statement ends the execution of an entire loop.

var sum = 0
for number in 1...10 {
    sum += number
    if sum > 15 {
        break
    }
}

Labeled Statements: You can label a loop or condition statement, and then use break or continue with that label, allowing for more precise control transfer.
```
outerLoop: for i in 1...5 {
    for j in 1...5 {
        if i * j == 12 {
            break outerLoop
        }
    }
}
```

Remember, when using loops, always ensure there's a clear exit condition to avoid infinite loops, which could cause your program to become unresponsive.

Looping through arrays with for-in in Swift:
Description: Swift's for-in loop is a concise way to iterate over each element in an array.
```
let numbers = [1, 2, 3, 4, 5]
for number in numbers {
    print(number)
}
```
Nested loops in Swift programming:
Description: You can nest one or more loops inside another to create more complex iteration patterns.
```
for i in 1...3 {
    for j in 1...3 {
        print("(\(i), \(j))")
    }
}
```
Swift repeat-while loop usage:
Description: The repeat-while loop in Swift repeats a block of code until a condition becomes false.
```
var count = 0
repeat {
    print("Count: \(count)")
    count += 1
} while count < 5
```
Loop control flow statements in Swift:
Description: Swift provides break and continue statements to control the flow of a loop.
```
for i in 1...5 {
    if i == 3 {
        break // exits the loop when i is 3
    }
    print(i)
}
```
Handling ranges with loops in Swift:
Description: Ranges can be used to define a sequence of values to iterate over.
```
for number in stride(from: 0, to: 10, by: 2) {
    print(number)
}
```
Swift break and continue statements in loops:
Description: break is used to exit a loop prematurely, and continue is used to skip the rest of the code inside the loop for the current iteration.
```
for i in 1...5 {
    if i % 2 == 0 {
        continue // skips even numbers
    }
    print(i)
}
```