Ruby中的決策錯誤

我被困在決策部分。當答案變量是N（當我鍵入n這意味着我不希望在不同的行打印文本）和標誌着變量爲Y（當我Y型那就意味着我不想打印帶引號的文本），我收到消息：答案'Y'無效。程序正在終止。下面是代碼：Ruby中的決策錯誤

def multiFunctionalPrinter 
    puts "How many times do you want to print?" 
    number = gets 
    puts "-------------------------------------------" 
    puts "What do you want to print?" 
    text = gets.chomp             #chomping variable to format it for decision making 
    puts "-------------------------------------------" 
    puts "Do you want to print in different lines (Y or N)?" 
    answer = gets.chomp             #chomping variable to format it for decision making 
    puts "-------------------------------------------" 
    puts "Do you want to add quotation marks (') (Y or N)?" 
    marks = gets.chomp             #chomping variable to format it for decision making 

    if answer == "Y" && marks == "Y"          # Different lines: ON , Quotation marks: ON 
     1.upto(number.to_i) {puts "'" + text.to_s + "'"} 
    elsif answer == "Y" && marks == "N"         # Different lines: ON , Quotation marks: OFF 
     1.upto(number.to_i) {puts text.to_s} 
    elsif answer == "Y" && marks != "Y" || marks != "N"     # Different lines: ON , Quotation marks: INVALID 
     puts "Answer '#{marks}' is invalid. Program is terminating." 
    elsif answer == "N" && marks == "Y"         # Different lines: OFF , Quotation marks: ON 
     puts "Do you want to split what you print? (Y or N)" 
     answer2 = gets.chomp 
     if answer2 == "Y"            # Split: ON 
      1.upto(number.to_i) {print "'" + text.to_s + "' "} 
      print "\n" 
     elsif answer2 == "N"            # Split: OFF 
      1.upto(number.to_i) {print "'" + text.to_s + "'"} 
     else 
      puts "Answer '#{answer2}' is invalid. Program is terminating." 
     end 
    elsif answer == "N" && marks == "N"         # Different lines: OFF , Quotation marks: OFF 
     puts "Do you want to split what you print? (Y or N)" 
     answer2 = gets.chomp 
     if answer2 == "Y"            # Split: ON 
      1.upto(number.to_i) {print text.to_s + " "} 
     elsif answer2 == "N"            # Split: OFF 
      1.upto(number.to_i) {print text.to_s} 
     else 
      puts "Answer '#{answer}' is invalid. Program is terminating." 
     end 
    else 
     puts "Answer '#{answer}' or '#{marks}' is invalid. Program is terminating." 
    end 
    puts "--------------------------------------------" 
end 

multiFunctionalPrinter

我在做什麼錯？

來源

2015-06-14 Nikola

二元運算符&&的優先級高於||。
這意味着，這條線：

answer == "Y" && marks != "Y" || marks != "N"

是相當於

(answer == "Y" && marks != "Y") || marks != "N"

所以每當marks不同於"N"，聲明成立。

你應該如何解決你的問題是添加一堆括號。

answer == "Y" && (marks != "Y" || marks != "N")

來源

2015-06-14 15:58:44 Nax

邏輯的問題是在這條線：（！答案== 「Y」 & &標記= 「Y」）

elsif answer == "Y" && marks != "Y" || marks != "N"

你的腳本是希望看到現在||標記！=「N」。它在語句到達語句之前進行評估，因爲答案是「N」，標記是「Y」（answer ==「Y」& & marks！=「Y」）的計算結果爲true。

你想擁有左右括號或表達式因此上述線路將變爲：

elsif answer == "Y" && (marks != "Y" || marks != "N")

和程序應按照您的想法。

來源

2015-06-14 16:02:03 wpickett

Ruby中的決策錯誤

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