Swift Examples
Dave Braunschweig
Overview
The following examples demonstrate data types, arithmetic operations, and input in Swift.
Data Types
// This program demonstrates variables, literal constants, and data types. var i: Int var d: Double var s: String var b: Bool i = 1234567890 d = 1.23456789012345 s = "string" b = true print("Integer i =", i) print("Double d =", d) print("String s =", s) print("Boolean b =", b)
Output
Integer i = 1234567890 Double d = 1.23456789012345 String s = string Boolean b = true
Discussion
Each code element represents:
//
begins a commentvar i: Int
defines an integer variable named ivar d: Double
defines a double floating-point variable named dvar s: String
defines a string variable named svar b: Bool
defines a Boolean variable named bi = , d = , s =, b =
assign literal values to the corresponding variablesprint()
calls the print function
Arithmetic
// This program demonstrates arithmetic operations. var a: Int var b: Int a = 3 b = 2 print("a =", a) print("b =", b) print("a + b =", (a + b)) print("a - b =", (a - b)) print("a * b =", a * b) print("a / b =", a / b) print("a % b =", (a % b))
Output
a = 3 b = 2 a + b = 5 a - b = 1 a * b = 6 a / b = 1 a % b = 1
Discussion
Each new code element represents:
+, -, *, /, and %
represent addition, subtraction, multiplication, division, and modulus, respectively.
Temperature
// This program converts a Fahrenheit temperature to Celsius. // // References: // https://www.mathsisfun.com/temperature-conversion.html // https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/TheBasics.html var fahrenheit: Double var celsius: Double print("Enter Fahrenheit temperature:") fahrenheit = Double(readLine()!)! celsius = (fahrenheit - 32) * 5 / 9 print(String(fahrenheit) + "° Fahrenheit is " + String(celsius) + "° Celsius")
Output
Enter Fahrenheit temperature: 100 100.0° Fahrenheit is 37.7777777777778° Celsius
Discussion
Each new code element represents:
readline()!
reads the next line from standard inputDouble()!
converts the input to a double floating-point valueString()
converts the output numeric value to a string