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Swift – Constants ”; Previous Next What is Constant in Swift? Constants refer to fixed values that a program may not alter during its execution. Constants can be of any data type like an integer, float, character, double, or a string literal. There are enumeration constants as well. They are treated just like regular variables except for the fact that their values cannot be modified after their definition. Declaring Swift Constant Constants are used to store values that won’t change throughout the whole execution of the program. They are always declared before their use and they are declared using the let keyword. Syntax Following is the syntax of constant − let number = 10 Example Swift program to demonstrate how to declare constants. import Foundation // Declaring constant let constA = 42 print(“Constant:”, constA) Output Constant: 42 If we try to assign value to a constant, then we will get an error just like in the below example − import Foundation // Declaring constant let constA = 42 print(“Constant:”, constA) // Assigning value to a constant constA = 43 print(“Constant:”, constA) Output main.swift:8:1: error: cannot assign to value: ”constA” is a ”let” constant constA = 43 ^~~~~~ main.swift:4:1: note: change ”let” to ”var” to make it mutable let constA = 42 ^~~ var We can also declare multiple constants in a single line. Where each constant has its values and is separated by commas. Syntax Following is the syntax of multiple constants − let constantA = value, constantB = value, constantC = value Example Swift program to demonstrate how to declare multiple constants in a single line. import Foundation // Declaring multiple constants let constA = 42, constB = 23, constC = 33 print(“Constant 1:”, constA) print(“Constant 2:”, constB) print(“Constant 3:”, constC) Output Constant 1: 42 Constant 2: 23 Constant 3: 33 Type Annotations with constants Type annotation is used to define what type of value should be stored in the constant at the time of declaration. While declaring a constant we can specify type annotation by placing a colon after the constant name followed by the type. Type annotation is rarely used if we provide an initial value at the time of declaring a constant because Swift will automatically infer the type of the constant according to the assigned value. For example, let myValue = “hello”, so the type of myValue constant is String because we assigned a string value to the constant. Syntax Following is the syntax of type annotations − let constantName : Type = Value Example Swift program to demonstrate how to specify type annotation. import Foundation // Declaring constant with type annotation let myValue : String = “hello” print(“Constant:”, myValue) Output Constant: hello We can also define multiple constants of the same type in a single line. Where each constant name is separated by a comma. Syntax Following is the syntax of multiple constants − let constantA, constantB, constantC : Type Example Swift program to demonstrate how to specify multiple constants in single-type annotation. import Foundation // Declaring multiple constants in single-type annotation let myValue1, myValue2, myValue3 : String // Assigning values myValue1 = “Hello” myValue2 = “Tutorials” myValue3 = “point” print(“Constant Value 1:”, myValue1) print(“Constant Value 2:”, myValue2) print(“Constant Value 3:”, myValue3) Output Constant Value 1: Hello Constant Value 2: Tutorials Constant Value 3: point Naming Constants in Swift Naming a constant is very important. They should have a unique name. You are not allowed to store two constants with the same name if you try to do you will get an error. Swift provides the following rules for naming a constant − Constant names can contain any character including unicode characters. For example, let 你好 = “你好世界”. The constant name should not contain whitespace characters, mathematical symbols, arrows, private-se Unicode scalar values, or line and box drawing characters. The name of a constant can be composed of letters, digits, and the underscore character. It must begin with either a letter or an underscore. For example, let myValue = 34. Upper and lowercase letters are distinct because Swift is case-sensitive. For example, let value and let Value are two different constants. Constant names should not begin with a number. You are not allowed to re-declare a constant with the same name. Or cannot change into another type. You are not allowed to change a constant into a variable or vice versa. If you want to declare a constant name the same as a reserved keyword, then use backticks(`) before the name of the constant. For example, let ”var = “hello”. Printing Swift Constants You can print the current value of a constant or variable using the print() function. You can interpolate a variable value by wrapping the name in parentheses and escaping it with a backslash before the opening parenthesis. Example Swift program to print constant. import Foundation // Declaring constants let constA = “Godzilla” let constB = 1000.00 // Displaying constant print(“Value of (constA) is more than (constB) millions”) Output Value of Godzilla is more than 1000.0 millions Print Page Previous Next Advertisements ”;

Swift – Operators ”; Previous Next What is an Operator in Swift? An operator is a symbol that tells the compiler to perform specific mathematical or logical manipulations. Or we can say that operators are special symbols that are used to perform specific operations between one or more operands. For example, to add two numbers such as 34 and 21 we will use the + operator (34 + 21 = 55). Type of Operators in Swift Swift supports the following types of operators − Arithmetic Operators Comparison Operators Logical Operators Bitwise Operators Assignment Operators Range Operators Misc Operators Let”s discuss each operator separately in detail. Swift Arithmetic Operators Arithmetic operators are used to perform mathematic operations like addition, division, multiplication, etc. on the given operands. They always work on two operands but the type of these operands should be the same. Swift supports the following arithmetic operators − Operator Name Example + Addition 20 + 30 = 50 – Subtraction 30 – 10 = 20 * Multiplication 10 * 10 = 100 / Division 20 / 5 = 4 % Modulus 10 % 2 = 0 Swift Comparison Operators Comparison operators are used to compare two operands and find the relationship between them. They return the result into a boolean(either true or false). Swift supports the following comparison operators − Operator Name Example (==) Equal 10 == 10 = true != Not Equal 34 != 30 = true > Greater than 90 > 34 = true < Less than 12 < 34 = true >= Greater than or Equal to 30 >= 10 = true <= Less than or Equal to 10 <= 32 = true Swift Logical Operators Logical operators are used to perform logical operations between the given expressions. It can also make decisions on multiple conditions. It generally works with Boolean values. Swift supports the following logical operators − Operator Name Example && Logical AND X && Y || Logical OR X || Y ! Logical NOT !X Swift Bitwise Operators Bitwise operators are used to manipulate individual bits of the integer. They are commonly used to perform bit-level operations. Swift supports the following bitwise operators − Operator Name Example & Bitwise AND X & Y | Bitwise OR X | Y ^ Bitwise XOR X ^ Y ~ Bitwise NOT ~X << Left Shift X << Y >> Right Shift X >> Y Swift Assignment Operators Assignment operators are used to assign and update the value of the given variable with the new value. Swift supports the following assignment operators − Operator Name Example (=) Assignment X = 10 += Assignment Add X = X + 12 -= Assignment Subtract X = X – 12 *= Assignment Multiply X = X * 12 /= Assignment Divide X = X / 12 %= Assignment Modulus X = X % 12 <<= Assignment Left Shift X = X << 12 >>= Assignment Right Shift X = X >> 12 &= Bitwise AND Assignment X = X & 12 ^= Bitwise Exclusive OR Assignment X = X ^12 |= Bitwise Inclusive OR Assignment X = X | 12 Swift Misc Operators Apart from the general operators Swift also supports some special operators and they are − Operator Name Example – Unary Minus -9 + Unary Plus 2 Condition ? X : Y Ternary Conditional If Condition is true ? Then value X : Otherwise value Y Swift Advance Operators Apart from the basic operators Swift also provides some advanced operators that are used to manipulate complex values and they are − Arithmetic Overflow Operators Identity Operators Identity Operators Let”s discuss each operator separately in detail. Swift Arithmetic Overflow Operators Arithmetic overflow operators are used to perform arithmetic operations and handle overflow very well if occurs. Or we can say that arithmetic operators work with those integers whose value may exceed the maximum or minimum bound. Swift supports the following arithmetic overflow operators − Operator Name Example &+ Overflow Addition Num1 &+ Num2 &- Overflow Subtraction Num1 &- Num2 &* Overflow Multiplication Num1 &* Num2 Swift Identity Operators Identity operators are used to determine whether the given variable refers to the same instance or not. These operators work with objects and classes. They are referenced type operators.

Swift – Logical Operators ”; Previous Next Logical Operator in Swift Logical operators are used to perform logical operations on multiple expressions together. They always return boolean values either true or false. They are commonly used with conditional statements and loops to return decisions according to the boolean conditions. You can also combine them to manipulate boolean values while dealing with complex expressions. Swift supports the following logical operators − Operator Name Example && AND A && B = false || OR A || B = true ! NOT !(A && B) = true AND Operator in Swift The AND operator returns true if both the given expressions are true. If any one of the expressions is false, then this operator will return false. It is an infix operator means this operator only works when you place it in between two operands. Syntax Following is the syntax of the AND operator − var result = expression1 && expression2 Example Swift program to perform logical AND operation between two expressions using AND operator (&&). import Foundation let age = 22 let height = 185 if (age > 18) && (height > 182){ print(“You are eligible for the Police exam”) } else { print(“You are not eligible”) } Output You are eligible for the Police exam OR Operator in Swift The OR operator returns true if only one of the expressions among the two given expressions is true. If both the expressions are false, then this operator will return false. It is an infix operator means it will be placed between two operands to perform its action. Syntax Following is the syntax of the OR operator − var result = expression1 || expression2 Example Swift program to perform logical OR operation between two expressions using OR operator (||). import Foundation let marks = 640 let experience = 3 if (marks > 500) || (experience > 4){ print(“You are eligible for the PO Post”) } else { print(“You are not eligible”) } Output You are eligible for the PO Post NOT Operator in Swift A NOT operator is used to invert the boolean value. If the value is true, then it will convert into false. Whereas if the value is false then it will convert into true. It is a prefix operator and is placed just before the expression whose value you want to invert. Syntax Following is the syntax of the NOT operator − !(expression1 && expression2) Example Swift program to perform logical NOT operation on the expressions using NOT operator (!). import Foundation let x = 20 let y = 40 // Here expression gives a true result but NOT operator converts it into a false if !(x > 0 && y > 0) { print(“Given values are greater than 0”) } else { print(“Given values are less than 0”) } Output Given values are less than 0 Combining Logical Operators in Swift In Swift, we can also combine multiple logical operators in a single expression. It will create a long compound expression. As we know AND and OR are left-associative so in the compound expression the left-side expression will evaluate first. Example Swift program to combine multiple logical operators. import Foundation let password = “vsv@v3″ let username = “mona” let mainPassword = “MO@12s” if (password == “XP123” || username == “mona”) && mainPassword == “MO@12s”{ print(“Welcome to the digital locker”) } else { print(“Error!!! Please enter correct detail”) } Output Welcome to the digital locker swift_operators.htm Print Page Previous Next Advertisements ”;