Difference between revisions of "Swift Live Reference"

Latest revision as of 12:14, 11 February 2023

Within these castle walls be forged Mavens of Computer Science ...

— Merlin, The Coder

Comments[edit]

Humans use comments to document code for other humans. They have no effect on the program's operation itself.

Single-line comments[edit]

Multi-line comments[edit]

Output[edit]

print[edit]

print with separator[edit]

print with terminator[edit]

Types[edit]

In Swift, it is customary to capitalize all types.

Int: A signed integer value type
Float: A single-precision, floating-point value type
Double: A double-precision, floating-point value type
String: A Unicode string value that is a collection of characters

Constant and Variable Declarations[edit]

Constant declarations[edit]

Constants (named values that should never change) use the let keyword.

Variable Declarations[edit]

Variables (named values that could change) use the var keyword.

Control Structures[edit]

Control structures are used to alter the otherwise sequential flow of a program.

Conditionals[edit]

Conditionals are used to execute a segment of code if a condition is met.

if[edit]

else[edit]

if n < 10 {
    print("n is less than 10")
} else {
    print("n is not less than 10")
}

switch[edit]

switch n {
    case 0:
        print("n is zero")
    case 1:
        print("n is one")
    default:
        print("n is neither one nor zero")
}

Loops[edit]

Loops are used to repeat a segment of code until a condition is met.

for[edit]

The for loop is helpful when the number of iterations is known.

// From zero up to but excluding ten
for n in 0 ..< 10 {
    print(n)
}

// From one up to and including 10
for n in 1 ... 10 {
    print(n)
}

while[edit]

The while loop is helpful when the condition might initially be false and the statements should not be executed.

while n < 10 {
    n += 1
}

repeat while[edit]

The repeat while loop is helpful when the statements should be executed at least once.

repeat {
    n += 1
} while n < 10

References[edit]

https://developer.apple.com/documentation/swift

@@ Line 1: / Line 1: @@
 == Comments ==
-Comments are used by humans to document code for other humans.  They have no effect on the program itself.
+Humans use ''comments'' to document code for other humans. They have no effect on the program's operation itself.
 === Single-line comments ===
-<syntaxhighlight lang="swift">
+{{CodeExplorer
+|exerciseID=1
+|height=100
+|language=swift
+|initialCode=
 // single-line comments begin with two slashes
-</syntaxhighlight>
+}}
 === Multi-line comments ===
-<syntaxhighlight lang="swift">
+{{CodeExplorer
+|exerciseID=2
+|height=100
+|language=swift
+|initialCode=
 /* multi-line comments begin with slash-star
     and continue
     and continue
     until a closing star-slash */
-</syntaxhighlight>
+}}
+== Output ==
+=== print ===
+{{CodeExplorer
+|exerciseID=3
+|height=100
+|language=swift
+|initialCode=
+print("Hello, World!")
+}}
+=== print with separator ===
+{{CodeExplorer
+|exerciseID=4
+|height=100
+|language=swift
+|initialCode=
+print("to", "ease", "another's", "heartache", separator: "*")
+}}
+=== print with terminator ===
+{{CodeExplorer
+|exerciseID=5
+|height=100
+|language=swift
+|initialCode=
+print("to", "ease", "another's", "heartache", separator: "*", terminator: "<>")
+print("is", "to", "forget", "one's", "own", separator: "/")
+}}
+== Types ==
+In Swift, it is customary to capitalize all types.
+;Int:A signed integer value type
+;Float:A single-precision, floating-point value type
+;Double:A double-precision, floating-point value type
+;String:A Unicode string value that is a collection of characters
+== Constant and Variable Declarations ==
+=== Constant declarations ===
+Constants (named values that should never change) use the '''let''' keyword.
+{{CodeExplorer
+|exerciseID=6
+|height=100
+|language=swift
+|initialCode=
+let gravity = 9.81 // meters per second per second
+print(gravity)
+}}
+=== Variable Declarations ===
+Variables (named values that could change) use the '''var''' keyword.
+{{CodeExplorer
+|exerciseID=7
+|height=100
+|language=swift
+|initialCode=
+var currentTemperature = 23.1 // degrees celsius
+print(currentTemperature)
+}}
 == Control Structures ==
 Control structures are used to alter the otherwise sequential flow of a program.
 === Conditionals ===
-Conditionals are used to execute a segment of code based upon a condition being met.
+Conditionals are used to execute a segment of code if a condition is met.
 ==== if ====
-<syntaxhighlight lang="swift">
+{{CodeExplorer
+|exerciseID=9
+|height=100
+|language=swift
+|initialCode=
+var n = 7
 if n < 10 {
      print("n is less than 10")
 }
-</syntaxhighlight>
+}}
 ==== else ====
 <syntaxhighlight lang="swift">
@@ Line 31: / Line 106: @@
 </syntaxhighlight>
 ==== switch ====
+<syntaxhighlight lang="swift">
+switch n {
+    case 0:
+        print("n is zero")
+    case 1:
+        print("n is one")
+    default:
+        print("n is neither one nor zero")
+}
+</syntaxhighlight>
 === Loops ===
 Loops are used to repeat a segment of code until a condition is met.
 ==== for ====
+The '''for''' loop is helpful when the number of iterations is known.
 <syntaxhighlight lang="swift">
+// From zero up to but excluding ten
 for n in 0 ..< 10 {
+    print(n)
+}
+// From one up to and including 10
+for n in 1 ... 10 {
      print(n)
 }
 </syntaxhighlight>
 ==== while ====
+The '''while''' loop is helpful when the condition might initially be false and the statements should not be executed.
 <syntaxhighlight lang="swift">
 while n < 10 {
@@ Line 45: / Line 139: @@
 }
 </syntaxhighlight>
 ==== repeat while ====
+The '''repeat while''' loop is helpful when the statements should be executed ''at least'' once.
 <syntaxhighlight lang="swift">
 repeat {
@@ Line 51: / Line 147: @@
 } while n < 10
 </syntaxhighlight>
+== References ==
+* https://developer.apple.com/documentation/swift