初识Go
意外关注到一位牛人的微信，提到了2014年他推荐的编程语言是Go。于是乎饶有兴趣的淘了一本书《Go语言程序设计》，学习起来。
第一章的练习题我的答案如下：
1 // Copyright © 2010-12 Qtrac Ltd. 2 // 3 // This program or package and any associated files are licensed under the 4 // Apache License, Version 2.0 (the "License"); you may not use these files 5 // except in compliance with the License. You can get a copy of the License 6 // at: http://www.apache.org/licenses/LICENSE-2.0. 7 // 8 // Unless required by applicable law or agreed to in writing, software 9 // distributed under the License is distributed on an "AS IS" BASIS, 10 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 11 // See the License for the specific language governing permissions and 12 // limitations under the License. 13 14 package main 15 16 import ( 17 "fmt" 18 "log" 19 "os" 20 "path/filepath" 21 "strings" 22 ) 23 24 func main() { 25 if len(os.Args) == 1 { 26 fmt.Printf("usage: %s <whole-number>\n", filepath.Base(os.Args[0])) 27 os.Exit(1) 28 } 29 30 drawBar := false 31 stringOfDigits := "" 32 33 if len(os.Args) == 2 { 34 if os.Args[1] == "-h" || os.Args[1] == "--help" { 35 fmt.Printf("usage: %s [-b|--bar] <whole-number>\n-b --bar draw an underbar and an overbar\n", filepath.Base(os.Args[0])) 36 os.Exit(1) 37 } else { 38 drawBar = false 39 stringOfDigits = os.Args[1] 40 } 41 } 42 43 if len(os.Args) == 3 { 44 if os.Args[1] == "-b" || os.Args[1] == "--bar" { 45 drawBar = true 46 stringOfDigits = os.Args[2] 47 } 48 } 49 50 for row := range bigDigits[0] { 51 52 line := "" 53 for column := range stringOfDigits { 54 digit := stringOfDigits[column] - '0' 55 if 0 <= digit && digit <= 9 { 56 line += bigDigits[digit][row] + " " 57 } else { 58 log.Fatal("invalid whole number") 59 } 60 } 61 62 if drawBar && row == 0 { 63 fmt.Println(strings.Repeat("*", len(line))) 64 } 65 fmt.Println(line) 66 if drawBar && row == len(bigDigits[0])-1 { 67 fmt.Println(strings.Repeat("*", len(line))) 68 } 69 } 70 71 if drawBar { 72 } 73 } 74 75 var bigDigits = [][]string{ 76 {" 000 ", 77 " 0 0 ", 78 "0 0", 79 "0 0", 80 "0 0", 81 " 0 0 ", 82 " 000 "}, 83 {" 1 ", "11 ", " 1 ", " 1 ", " 1 ", " 1 ", "111"}, 84 {" 222 ", "2 2", " 2 ", " 2 ", " 2 ", "2 ", "22222"}, 85 {" 333 ", "3 3", " 3", " 33 ", " 3", "3 3", " 333 "}, 86 {" 4 ", " 44 ", " 4 4 ", "4 4 ", "444444", " 4 ", 87 " 4 "}, 88 {"55555", "5 ", "5 ", " 555 ", " 5", "5 5", " 555 "}, 89 {" 666 ", "6 ", "6 ", "6666 ", "6 6", "6 6", " 666 "}, 90 {"77777", " 7", " 7 ", " 7 ", " 7 ", "7 ", "7 "}, 91 {" 888 ", "8 8", "8 8", " 888 ", "8 8", "8 8", " 888 "}, 92 {" 9999", "9 9", "9 9", " 9999", " 9", " 9", " 9"}, 93 }
