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Programming Fundamentals/Variable Examples Swift
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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 comment
var i: Int defines an integer variable named i
var d: Double defines a double floating-point variable named d
var s: String defines a string variable named s
var b: Bool defines a Boolean variable named b
i = , d = , s =, b = assign literal values to the corresponding variables
print() 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 input
Double()! converts the input to a double floating-point value
String() converts the output numeric value to a string
References
Wikiversity: Computer Programming