Basic syntax comparison of Swift and C #

Recently, Apple announced and released a beta version of the newSwift programming LanguageFor building IOS and OSX applications. Swift is a modern language with the power of objective-c without the "baggage of C." While we can ' t argue that objective-c have it ' s difficulties being tied closely to C, but the real question is ... How does Swift compare to a modern language like C #?

Please, keep-in-mind-this-post is not supposed-to-be-an Apple vs Microsoft post. There is a lot of developers so use C # every day and the purpose of this post was to help them understand what Swift off ERs at a language level compared to C #. And, before you start the "apples and oranges" arguments, it's worth pointing out of that usingXamarinYou can develop IOS and OSX apps using C #.

Now let the code mostly speak for itself ...

Code Comments

Both languages support the same syntax for code comments; The familiar C-style comments.

1. Code Comment
   
2. 
   
3. /* Multi Line
   
4. Code Comment */

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Declaring Constants and Variables

Swift, like C #, is a type safe language. It also supports type inference so you don't have to specify the type when declaring the variables as the compiler can INF ER (or detect) the type by evaluating the assignment of the variable. While C # is slightly more verbose when declaring constants; Both languages is just as elegant at declaring variables using type inference.

1. Declare Constant
   
2. C#
   
3. const int legalage = 18;
   
4. 
   
5. Swift
   
6. Let Legalage = 18
   
7. 
   
8. Declare Variable
   
9. C#
   
10. var legalage = 18;
    
11. 
    
12. Swift
    
13. var legalage = 18

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While type inference are nice, if you don't immediately assign a value to the variable your need to explicitly spe Cify the type of the variable.

1. Type Annotation
   
2. C#
   
3. String FirstName;
   
4. 
   
5. Swift
   
6. var firstname:string

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Notice the lack of the semi-colon in Swift. Yes, Swift is a mostly c-style syntax without requiring semi-colons. Swift does support and require the use of semi-colons if you want to has multiple code statements on the same line.

Variable Names and Unicode

Both languages support the use of the Unicode characters as variable names. Basically, you could use emoticons or other NON-ASCII characters as variable names if you want and who does that anyway?

Integer Bounds

Both languages has static constants for accessing, the minimum and maximum bounds for the different Integer types.

1. Integer Bounds
   
2. C#
   
3. var a = Int32.minvalue;
   
4. var B = Int32.MaxValue;
   
5. 
   
6. Swift
   
7. var a = Int32.min
   
8. var B = Int32.max

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Type Inference

Both languages, as mentioned above, support type inference where the compiler are able to detect what type the declared Var Iable is from it ' s immediate assignment.

1. Type Inference
   
2. C#
   
3. var a = 3; Integer
   
4. var B = 0.14//double
   
5. var C = a + B; Double
   
6. 
   
7. Swift
   
8. var a = 3//integer
   
9. var B = 0.14//double
   
10. var C = a + b//double

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Also in the above type inference example you ' ll notice so when you declare a variable and immediately assign a value tha T is the result of 2 other variables it would still infer the type.

String Comparison

Both has similar methods of comparing strings.

1. String Comparison
   
2. C#
   
3. var a = "one";
   
4. var B = "one";
   
5. if (a = = b) {
   
6. Both variables is considered equal
   
7. }
   
8. 
   
9. Swift
   
10. var a = "one"
    
11. var B = "One"
    
12. If a = = b {
    
13. Both variables is considered equal
    
14. }

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The both also has similar methods of detecting if the beginning or ending of the string match ' s a specified string.

1. C#
   
2. var s = "Some Value";
   
3. if (S.startswith ("Some")) {
   
4. The string starts with the value
   
5. }
   
6. if (S.endswith ("Value")) {
   
7. The string ends with the value
   
8. }
   
9. 
   
10. Swift
    
11. var s = "Some Value"
    
12. If S.hasprefix ("Some") {
    
13. The string starts with the value
    
14. }
    
15. If S.hassuffix ("Value") {
    
16. The string ends with the value
    
17. }

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Notice from the above example that parenthesis is not required with IF statements in Swift.

String Upper or Lower case

Both languages support similar methods of converting strings to Upper or Lower case.

1. String Upper and Lower case
   
2. C#
   
3. var s = "some Value";
   
4. var uppers = S.toupper ();
   
5. var lowers = S.tolower ();
   
6. 
   
7. Swift
   
8. var s = "Some Value"
   
9. var uppers = s.uppercasestring
   
10. var lowers = s.lowercasestring

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Declaring Arrays

Both languages support declaring and assigning Arrays using a single line of code.

1. Declare Arrays on single line
   
2. 
   
3. String Array
   
4. C#
   
5. var arr = new string[] {"One", "one"};
   
6. 
   
7. Swift
   
8. var arr = ["One", "both"]
   
9. 
   
10. Integer Array
    
11. C#
    
12. var arr = new int[] {1, 2};
    
13. 
    
14. Swift
    
15. var arr = [1, 2];

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Working with Arrays

Working with Arrays has slight differences between the languages.

2. Iterating over Array
   
4. C#
   
6. foreach (var item in arr) {
   
8. Do something
   
10. }
    
12. 
    
14. Swift
    
16. For item in arr {
    
18. Do something
    
20. }
    
22. 
    
24. 
    
26. Get Item at Index
    
28. C#
    
30. var item = arr[0];
    
32. Swift
    
34. var item = arr[0]
    
36. 
    
38. 
    
40. Set Item at Index
    
42. C#
    
44. Arr[0] = "Value";
    
46. 
    
48. Swift
    
50. Arr[0] = "Value"
    
52. 
    
54. 
    
56. Is Array Empty?
    
58. C#
    
60. if (arr. Length = = 0) {
    
62. Array is empty
    
64. }
    
66. 
    
68. Swift
    
70. If Arr.isempty {
    
72. Array is empty
    
74. }
    
76. 
    
78. 
    
80. Add Item to Array
    
82. C#
    
84. Array.resize (ref arr, arr.) Length + 1);
    
86. Arr[arr. LENGTH-1] = "three";
    
88. 
    
90. Swift
    
92. Arr.append ("three")
    
94. Or
    
96. Arr + = "three"
    
98. 
    
100. 
     
102. Remove Item at Index
     
104. C#
     
106. var list = arr. ToList ();
     
108. List. RemoveAt (0);
     
110. var newArr = list. ToArray ();
     
112. 
     
114. Swift
     
116. var newArr = arr.removeatindex (0)

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Declaring dictionaries

Both languages support similar methods of declaring dictionaries.

1. Declaring dictionaries
   
2. C#
   
3. var dict = new dictionary<string, string> ();
   
4. var dict2 = new dictionary<string, string>
   
5. {
   
6. {"Tyo", "Tokyo"},
   
7. {"DUB", "Dublin"}
   
8. };
   
9. 
   
10. Swift
    
11. var dict = dictionary<string, string> ()
    
12. var dict2 = ["Tyo": "Tokyo", "DUB": "Dublin"]

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Working with Dictionaries

Working with dictionaries has slight differences between the languages.

2. Iterate over Dictionary
   
4. C#
   
6. foreach (var item in dict) {
   
8. var key = Item. Key;
   
10. var value = Item. Value;
    
12. }
    
14. 
    
16. Swift
    
18. For (key, value) in Dict {
    
20. Key variable contains key of item
    
22. Value variable contains value of item
    
24. }
    
26. 
    
28. Get Item in Dictionary by Key
    
30. C#
    
32. var item = dict["Tyo"];
    
34. 
    
36. Swift
    
38. var item = dict["Tyo"]
    
40. 
    
42. 
    
44. Set Item in Dictionary by key
    
46. Or add if key doesn ' t exist
    
48. C#
    
50. dict["LHR"] = "London";
    
52. 
    
54. Swift
    
56. dict["LHR"] = "London"
    
58. 
    
60. 
    
62. Remove Item in Dictionary by key
    
64. C#
    
66. Dict. Remove ("LHR");
    
68. 
    
70. Swift
    
72. Dict.removevalueforkey ("DUB")

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For Loops

The above examples for Arrays and dictionaries already showed examples of using a for-in loops to iterate through the items In those collections. Here is some additional methods of iterating using a for loop.

1. Iterate from 1 through 5
   
2. C#
   
3. Using increment
   
4. for (var i = 1; I <= 5; i++) {
   
5. Do something with I
   
6. }
   
7. 
   
8. Swift
   
9. Using range
   
10. For I in 1...5 {
    
11. Do something with I
    
12. }
    
13. Using increment
    
14. for var i = 0; I <= 5; ++i {
    
15. Do something with I
    
16. }

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The range example of rather interesting in the method of shorthand it uses for it ' s definition.

Conditional statements

Both languages Support If ... Then conditional statements. Swift is a little different that it doesn ' t require parenthesis around the match conditions.

1. If then Else Conditional Statement
   
2. C#
   
3. if (i > 6) {
   
4. Do something
   
5. } else if (i > 3 && I <= 6) {
   
6. Do something
   
7. } else {
   
8. Do something
   
9. }
   
10. 
    
11. Swift
    
12. If I > 6 {
    
13. Do something
    
14. } else if i > 3 && i <= 6 {
    
15. Do something
    
16. } else {
    
17. Do something
    
18. }

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Switch Statement

Both languages Support Switch statements.

2. Switch statement
   
4. C#
   
6. var word = "A";
   
8. Switch (word) {
   
10. Case "A":
    
12. Do something
    
14. Break
    
16. Case "B":
    
18. Do something
    
20. Break
    
22. Default
    
24. Do something
    
26. Break
    
28. }
    
30. 
    
32. Swift
    
34. var word = "A"
    
36. Switch Word {
    
38. Case "A":
    
40. Do something
    
42. Case "B":
    
44. Do something
    
46. Default
    
48. Do something
    
50. }

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Switch statements is rather similar in both languages except so in Swift case statements don ' t automatically pass over to The next like in C #. As a result C # requires the use of the keywords to exit the Switch statement, unless you want to fall through to the Next case. While in Swift must use the "fallthrough" keyword-to-tell it-pass on through to the next case statement. More information on this can is found in the Swift documentation.

An additional feature, Swift supports with Switch statements are ranges within the case statements. This was something that C # does not support.

2. Switch Case Ranges
   
4. C#
   
6. switch (i) {
   
8. Case 1:
   
10. Case 2:
    
12. Case 3:
    
14. Do something
    
16. Break
    
18. Case 4:
    
20. Do something
    
22. Break
    
24. Default
    
26. Do something
    
28. Break
    
30. }
    
32. 
    
34. Swift
    
36. Switch I {
    
38. Case 1...3:
    
40. Do something
    
42. Case 4:
    
44. Do something
    
46. Default
    
48. Do something
    
50. }

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Functions

WhileFunctions is a much bigger comparisonTo is made, here's a basic example:

1. Function with Parameter and Return Value
   
2. C#
   
3. String SayHello (string name) {
   
4. Do something
   
5. }
   
6. 
   
7. Swift
   
8. Func SayHello (name:string), String {
   
9. Do something
   
10. }

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The PostBasic Comparison of Functions in C # and SwiftGoes to much more depth on Functions; As that was a much bigger comparison that could fit to this post.

Conclusion

This concludes my basic comparison of C # and Apple Swift programming languages. The languages is rather similar in many respects; At least in what I ' ve compared thus far. More language feature comparisons would have the to-wait for the future posts.

One of the bigger differences that's worth pointing out explicitly are the difference in what each language handles Array ' s. Arrays in Swift is extremely similar to the List<> class in C #; Which is what the most developers use today in C # instead of arrays anyway (unless performance requires it.)

You can find more information about the Swift programming language on Apple's site at the following links:https://developer.apple.com/swift/https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/

Basic syntax comparison of Swift and C #