Operators and Expressions (i)

Main.swift//Operator and expression (i)////Created by Goddog on 15/6/23. Copyright (c) 2015 Goddog.
All rights reserved.  Import Foundation//mark:-Assignment operator//with = as assignment operator var str = "Swift" var pi:double = 3.14 var Visited:bool = true Var str1:string = str//swift does not support continuous assignment var a:int//var b = a = Ten//mark:-Arithmetic operator//Add, subtract, multiply, divide//pay attention to the remainder operation: the operator is not an integer on both sides of the required operators, and supports the Floating-point var a1 = 12.1 var B1 = 4.2 var mod = a1% B1 println (mod) println ("negative modulus negative: \ (-12.3-2.4)")//Return negative number println ("Negative number modulo positive: \  (-21.2% 3) ")//Return negative println (" positive modulus negative: \ (24.4%-7.2) ")//Return positive println (" positive modulo 0.0:\ (4% 0.0) ")//Return Nan println (" negative modulus 0.0:\ (-2% 0.0)//Return nan println ("0 pairs of positive numbers modulo: \ (0 2)")//Return 0.0 println ("0 to 0.0 modulo \ (0% 0.0)")//Return nan//self-add and decrement: 1. Put the + + on the left side, first add one to the operand, and then put it in the expression In//2. Put + + on the right, first put the operand in the expression, and then add the operand to a var a2 = 5 var D2 = 1 var b2 = a2++ + 1 var c2 = ++d2 + 1 println ("A2 is: \ (a 2), B2 is: \ (b2), C2 is: \ (c2) ") var a3 = 4.2 println (" A of 5 Parties: \ (POW (a3,5)) ") println (" A's square root: \ (sqrt (A3)) ") println (" The random number between 0~10 " : \ (arc4random ()%) ") PRIntln (The Sin function value of "1.2: \ (sin (1.2))")//mark:-overflow operator//swift does not allow integer variables or constants to be assigned a value that exceeds the range of its number var f:int16 = 32767//f = f + 1//Super //&+, &-, &*, &/, &% f = f &+ 1//value overflow f = f &-100//value underflow let G = ten let k = g &/0/ /Get 0 Let q = g &% 0//Get 0//mark:-bitwise operator//& bitwise AND, | bitwise OR, ^ bitwise XOR, ~ bitwise negation, << left shift operator, >> right shift operator//mark:-range operation //1. The closed range operator a...b is used to define a range from a~b (including A, b boundary) for all values, a cannot be greater than b var ranges = 2...6 for range in ranges {println (range)}//2. Half Open Range Operator: A.. < is used to define a range of all values from a~b (containing a, but not including B), for iterating over an array of appropriate var books = ["Swift", "Java", "OC", "PHP"] for index in 0..<books.count {pri  Ntln ("index+1 language is: \ (Books[index])"}//mark:-comparison operator//> >= < <= = = = = = =!== var K1 =  Nsmutablearray () var K2 = Nsmutablearray ()//Determines whether the contents of two objects are equal, outputs true println (k1 = = K2)//Determines whether two objects point to the same object, outputs false println (K1 = = = K2)//mark:-Logical operator//&& and, & not shorted with, | | Or, | Not short circuit OR,! Non, ^ xor//mark:-Three mesh operation var G1 = 2 var g2 = 4 var g3 = g1 > g2? "G1 Greater than G2" : "G1 is not much more than G2" println (G3)//mark:-Nil merge operator//a?? The function of B is to determine if the optional type variable A is nil, and if it is not nil, the actual value wrapped by the optional variable A is returned, otherwise the type of the default value B,b is the same as a let DefaultName = "Cao"//defines an optional type variable, and is not an empty var name1: String?
= "Liu Bei" println (name1?? defaultname)//define an optional type variable, and an empty var name2:string? println (name2? defaultname)//actually a?? b equals a! = nil? A!
 : b println ("Hello, world!")