Swift语言基础笔记(四)
发布时间:2020-12-14 06:40:28 所属栏目:百科 来源:网络整理
导读:通过前面几篇的学习,Swift的基础类型学习的差不多了,接下来就学习流程控制与条件语句和运算符 一、运算符 //: Playground - noun: a place where people can playimport UIKit//运算符Swift学习,+ - * / % += -= || | 注意不同类型需要显示强制转换var x
通过前面几篇的学习,Swift的基础类型学习的差不多了,接下来就学习流程控制与条件语句和运算符 一、运算符 //: Playground - noun: a place where people can play import UIKit //运算符Swift学习,+ - * / % > < += -= || && | & 注意不同类型需要显示强制转换 var x = 10; var y = 3; var z = 0; x/y Double(x)/Double(y); var xx = +x; var yy = -y; x += 9; if x > y{ print("10 > 3"); } var capacity = 30; var volume = 50; if x > y && capacity < volume{ print("Buy it"); } if x < y || capacity > volume{ print("Buy it"); }else{ print("not buy it"); } 二、循环语句 //: Playground - noun: a place where people can play import UIKit //循环语句有for、while、do-while for index in -99...99{ index; index*index; } var i = -99; for ; i <= 99 ; { i*i; i++; } for var a = -6.28; a <= 6.28; a += 0.1 { sin(a); } var ii = -99; var step = 1; for ; ii <= 99; ii += step{ ii * ii; step *= 2; } var a = 10; while a > 0{ a--; } var aWin = 0; var bWin = 0; var game = 0; while aWin < 3 && bWin < 3{ game++; let a = arc4random_uniform(6) + 1; let b = arc4random_uniform(6) + 1; print("a is (a),b is (b).",terminator:" "); if a > b{ print("A win"); bWin = 0; aWin++; }else if a < b{ print("B win"); aWin = 0; bWin++; }else{ print("a == b"); aWin = 0; bWin = 0; } } let winner = aWin == 3 ? "A" : "B"; print("After (game) games (winner) Win") print(""); var aaWin = false; var bbWin = false; var agame = 0; repeat{ game++; let a = arc4random_uniform(6) + 1; let b = arc4random_uniform(6) + 1; print("a is (a),terminator:" "); if a > b{ aaWin = true; }else if a < b{ bbWin = true; }else{ print("a == b"); } print(""); }while !aaWin && !bbWin; let awinner = aaWin ? "A" : "B"; print("After (awinner) Win") print(""); while true{ let a = arc4random_uniform(6) + 1; let b = arc4random_uniform(6) + 1; print("a is (a),b is (b)."); if a == b{ print("a == b"); continue; } let winner = a > b ? "A" : "B"; print("(winner) win!"); break; } 三、条件语句 switch if-else //: Playground - noun: a place where people can play import UIKit //条件语句 var count = 15 if a > 20{ print((a) > 20) }else{ print((a) <= 20) } let rating = "A"; switch rating{ case "a","A": print("Great"); case "b","B": print("Just so-so"); case "c","C": print("It's Bad"); default: print("Error") } let score = 100; switch score{ case 0: print("You got a egg") case 1..<60: print("You faild") case 60: print("Just passed") case 61..<80: print("Just so-so") case 80..<90: print("Good") case 90..<100: print("Great") case 100: print("Perfect!") default: print("Error score") } print("") //x^4 - y^2 = 15* x * y; findAnswer:for m in 1...300{ for n in i...300{ if m*m*m*m - n*n == 15*m*n{ print("m = (m),n = (n),left = (m*m*m*m - n*n),right = (15*m*n)"); break findAnswer; } } } //where语句的使用 let point = (3,5); switch point{ case let(x,y) where x == y: print("It's on the line x == y!"); case let(x,y) where x == -y: print("It's on the line x == -y!"); case let(x,y): print("It's just an ordinary point."); print("The point is (x),(y)"); } let age = 19; switch age{ case 10...19: print("You're a teenager."); default: print("You're not a teenager."); } if case 10...19 = age{ print("You're a teenager."); } if case 10...19 = age where age >= 18{ print("You're a teenager and in a college."); } let vector = (4,0); if case (let x,0) = vector where x > 2 && x < 5{ print("It's the vector"); } (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |