Loops in Swift

In this tutorial, we will learn about different types of loops in Swift. We will cover the basics of `for-in`, `while`, and `repeat-while` loops.

What is a Loop

A loop is a control flow statement that allows code to be executed repeatedly based on a condition.

Loops

Swift supports three types of loops: `for-in` loops, `while` loops, and `repeat-while` loops.

For-In Loop

A `for-in` loop is used when iterating over a sequence, such as arrays, ranges, or strings. The syntax for the for-in loop is:

for item in sequence {
    // Code block to be executed
}

While Loop

A `while` loop is used when the number of iterations is not known beforehand. The syntax for the while loop is:

while condition {
    // Code block to be executed
}

Repeat-While Loop

A `repeat-while` loop is similar to a `do-while` loop in other languages, where the code block is executed at least once before checking the condition. The syntax for the repeat-while loop is:

repeat {
    // Code block to be executed
} while condition

Example 1: Printing Numbers from 1 to 5 using For-In Loop

  1. Use a for-in loop to print numbers from 1 to 5.

Swift Program

for i in 1...5 {
    print(i, terminator: " ")
}

Output

1 2 3 4 5

Example 2: Printing Numbers from 1 to 3 using While Loop

  1. Declare an integer variable i and initialize it to 1.
  2. Use a while loop to print numbers from 1 to 3.

Swift Program

var i = 1
while i <= 3 {
    print(i, terminator: " ")
    i += 1
}

Output

1 2 3

Example 3: Printing Numbers from 1 to 3 using Repeat-While Loop

  1. Declare an integer variable i and initialize it to 1.
  2. Use a repeat-while loop to print numbers from 1 to 3.

Swift Program

var i = 1
repeat {
    print(i, terminator: " ")
    i += 1
} while i <= 3

Output

1 2 3