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POCreate a random within a range from an ArrayList within an Arraylist
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2013-09-29T00:39:35.107
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2013-09-29T00:59:19.907
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2013-09-29T00:48:13.310
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<p>I am at the end of my program here and Im trying to create a random number thats in an arraylist. I have the syntax below that Im using. I don't know how to write this, but I hope the code shows what I'm trying to accomplish. </p> <pre><code>import java.io.File; import java.io.IOException; import java.util.ArrayList; import java.util.Random; import java.util.Scanner; public class TriviaQuestionTester { /** * @param args * @throws IOException */ public static void main(String[] args) throws IOException { File gameFile = new File("trivia.txt"); String nextLine, category; int cat1 = 0; int cat2 = 0; int cat3 = 0; int cat4 = 0; int cat5 = 0; int cat6 = 0; int random1, random2, random3, random4, random5, random6; int totalScore = 0; int awardedPoints = 200; String answer; Random random = new Random(); Scanner inFile = new Scanner(gameFile); Scanner scanner = new Scanner(System.in); ArrayList <String> myList = new ArrayList<String>(); //append @ sign to first index of arraylist when we copy the text file into it. first line will //be the first category. category = "@"+ inFile.nextLine(); //add category to arraylist myList.add(category); //while textfile has another line of input, write that line into the arraylist. while (inFile.hasNextLine()){ nextLine = inFile.nextLine(); //check if the next line is blank. if it is, advance to the next line (as it must be a category) and append @ sign //before copying it into the arraylist. if it is not, write the line into the arraylist. if(nextLine.equals("")){ category = "@"+ inFile.nextLine(); myList.add(category); } else { myList.add(nextLine); } } //close the text file from reading inFile.close(); System.out.println("Steve's Crazy Trivia Game!!!!" ); System.out.println(""); //find categories by searching the contents of every arraylist index and looking for the @ sign. //when you find that, assign that into the respective variable. int q = 1; for(int j = 0; j < myList.size(); j++){ if(myList.get(j).contains("@")){ //System.out.println("Category found at " + j); if(q == 1){ cat1 = j; } if(q == 2){ cat2 = j; } if(q == 3){ cat3 = j; } if(q == 4){ cat4 = j; } if(q == 5){ cat5 = j; } if(q == 6){ cat6 = j; } q++; } } //first question //get category from variable, print it to user without the @ sign System.out.println("Category: " + myList.get(cat1).substring(1)); //generate a random number in a range 1 more than the index where the category is and 2 less than //where the next category is to get a question (always will be odd numbers) //Credit: Derek Teay random1 = random.nextInt(((cat2 - 2) - (cat1 + 1))) + (cat1 + 1); //debug code - shows the number generated //System.out.println("Random number: " + random1); //take the modulus of the random number. if there is a remainder, the number is odd, continue. //if there is not a remainder, number is even, generate a new number until the randomly generated //number is odd. while (random1 % 2 == 0){ random1 = random.nextInt(((cat2 - 2) - (cat1 + 1))) + (cat1 + 1); //debug code - shows the new random number if the first number isn't odd //System.out.println("New random number: " + random1); } //display the question to the user System.out.println("Question: " + myList.get(random1)); //accept user input System.out.print("Please type your answer: "); //store the user answer in a variable but lowercase answer = scanner.nextLine().toLowerCase(); System.out.println(); //display the officially correct answer from the arraylist //System.out.println("Answer: " + myList.get(random1 +1)); //if the user answer matches the official answer, tell them they're correct and award points - else //tell them they are incorrect // Display the officially correct answer from the arraylist String correctAnswer = myList.get(random1 +1); System.out.println("Answer: " + correctAnswer); // Instead use a variable // if the user answer matches the official answer, tell them they're // correct and award points // else tell them they suck LOL if(correctAnswer.equalsIgnoreCase(answer.trim())) { System.out.println("Correct!"); totalScore = totalScore + awardedPoints; System.out.println("You won " + awardedPoints); } else { System.out.println("You are incorrect"); } //display total accumulated points System.out.println("Your total points are: " + totalScore); //wait for user to hit any key before displaying the next question System.out.print("Hit Enter"); System.out.println(""); scanner.nextLine(); //second question //get category from variable, print it to user without the @ sign System.out.println("Category: " + myList.get(cat2).substring(1)); //generate a random number in a range 1 more than the index where the category is and 2 less than //where the next category is to get a question (always will be odd numbers) //Credit: Derek Teay random2 = random.nextInt(((cat3 - 2) - (cat2 + 1))) + (cat2 + 1); //take the modulus of the random number. if there is a remainder, the number is odd, continue. //if there is not a remainder, number is even, generate a new number until the randomly generated //number is odd. while (random2 % 2 == 0){ random2 = random.nextInt(((cat3 - 2) - (cat2 + 1))) + (cat2 + 1); } //display the question to the user System.out.println("Question: " + myList.get(random2 + 1)); //accept user input System.out.print("Please type your answer: "); //store the user answer in a variable but lowercase answer = scanner.nextLine().toLowerCase(); System.out.println(); //if the user answer matches the official answer, tell them they're correct and award points - else //tell them they are incorrect // Display the officially correct answer from the arraylist String correctAnswer1 = myList.get(random2 +1); System.out.println("Answer: " + correctAnswer1); // Instead use a variable // if the user answer matches the official answer, tell them they're // correct and award points // else tell them they suck LOL if(correctAnswer1.equalsIgnoreCase(answer.trim())) { System.out.println("Correct!"); totalScore = totalScore + awardedPoints; System.out.println("You won " + awardedPoints); } else { System.out.println("You are wrong again"); } //display total accumulated points System.out.println("Your total points are: " + totalScore); //wait for user to hit any key before displaying the next question System.out.print("Hit Enter"); System.out.println(""); scanner.nextLine(); //third question //get category from variable, print it to user without the @ sign System.out.println("Category: " + myList.get(cat3).substring(1)); //generate a random number in a range 1 more than the index where the category is and 2 less than //where the next category is to get a question (always will be odd numbers) //Credit: Derek Teay random3 = random.nextInt(((cat4 - 2) - (cat3 + 1))) + (cat3 + 1); //take the modulus of the random number. if there is a remainder, the number is odd, continue. //if there is not a remainder, number is even, generate a new number until the randomly generated //number is odd. while (random3 % 2 == 0){ random3 = random.nextInt(((cat4 - 2) - (cat3 + 1))) + (cat3 + 1); } //display the question to the user System.out.println("Question: " + myList.get(random3 + 1)); //accept user input System.out.print("Please type your answer: "); //store the user answer in a variable but lowercase answer = scanner.nextLine().toLowerCase(); System.out.println(); //if the user answer matches the official answer, tell them they're correct and award points - else //tell them they are incorrect // Display the officially correct answer from the arraylist String correctAnswer2 = myList.get(random3 +1); System.out.println("Answer: " + correctAnswer1); // Instead use a variable // if the user answer matches the official answer, tell them they're // correct and award points // else tell them they suck LOL if(correctAnswer2.equalsIgnoreCase(answer.trim())) { System.out.println("Correct!"); totalScore = totalScore + awardedPoints; System.out.println("You won " + awardedPoints); } else { System.out.println("Wow, you really stink"); } //display total accumulated points System.out.println("Your total points are: " + totalScore); //wait for user to hit any key before displaying the next question System.out.print("Hit Enter"); System.out.println(""); scanner.nextLine(); //fourth question //get category from variable, print it to user without the @ sign System.out.println("Category: " + myList.get(cat4).substring(1)); //generate a random number in a range 1 more than the index where the category is and 2 less than //where the next category is to get a question (always will be odd numbers) //Credit: Derek Teay random4 = random.nextInt(((cat5 - 2) - (cat4 + 1))) + (cat4 + 1); //take the modulus of the random number. if there is a remainder, the number is odd, continue. //if there is not a remainder, number is even, generate a new number until the randomly generated //number is odd. while (random4 % 2 == 0){ random4 = random.nextInt(((cat5 - 2) - (cat4 + 1))) + (cat4 + 1); } //display the question to the user System.out.println("Question: " + myList.get(random4 + 1)); //accept user input System.out.print("Please type your answer: "); //store the user answer in a variable but lowercase answer = scanner.nextLine().toLowerCase(); System.out.println(); //if the user answer matches the official answer, tell them they're correct and award points - else //tell them they are incorrect // Display the officially correct answer from the arraylist String correctAnswer3 = myList.get(random4 +1); System.out.println("Answer: " + correctAnswer3); // Instead use a variable // if the user answer matches the official answer, tell them they're // correct and award points // else tell them they suck LOL if(correctAnswer3.equalsIgnoreCase(answer.trim())) { System.out.println("Correct!"); totalScore = totalScore + awardedPoints; System.out.println("You won " + awardedPoints); } else { System.out.println("You are incorrect"); } //display total accumulated points System.out.println("Your total points are: " + totalScore); //wait for user to hit any key before displaying the next question System.out.print("Hit Enter"); System.out.println(""); scanner.nextLine(); //fifth question //get category from variable, print it to user without the @ sign //generate a random number in a range 1 more than the index where the category is and 2 less than //where the next category is to get a question (always will be odd numbers) //Credit: Derek Teay random5 = random.nextInt(((cat6 - 2) - ( cat5 + 1))) + (cat5 + 1); //take the modulus of the random number. if there is a remainder, the number is odd, continue. //if there is not a remainder, number is even, generate a new number until the randomly generated //number is odd. while (random5 % 2 == 0){ random5 = random.nextInt(((cat6 - 2) - (cat5 + 1))) + (cat5 + 1); } //display the question to the user System.out.println("Question: " + myList.get(random5 + 1)); //accept user input System.out.print("Please type your answer: "); //store the user answer in a variable but lowercase answer = scanner.nextLine().toLowerCase(); System.out.println(); //if the user answer matches the official answer, tell them they're correct and award points - else //tell them they are incorrect // Display the officially correct answer from the arraylist String correctAnswer4 = myList.get(random5 +1); System.out.println("Answer: " + correctAnswer4); // Instead use a variable // if the user answer matches the official answer, tell them they're // correct and award points // else tell them they suck LOL if(correctAnswer4.equalsIgnoreCase(answer.trim())) { System.out.println("Correct!"); totalScore = totalScore + awardedPoints; System.out.println("You won " + awardedPoints); } else { System.out.println("You are incorrect"); } //display total accumulated points System.out.println("Your total points are: " + totalScore); //wait for user to hit any key before displaying the next question System.out.print("Hit Enter"); System.out.println(""); scanner.nextLine(); //sixth question //get category from variable, print it to user without the @ sign System.out.println("Category: " + myList.get(cat6).substring(1)); //generate a random number in a range 1 more than the index where the category is and 2 less than //where the next category is to get a question (always will be odd numbers) //Credit: Derek Teay random6 = random.nextInt((cat6.maximum - cat6.minimum) + (cat6.minimum)); //take the modulus of the random number. if there is a remainder, the number is odd, continue. //if there is not a remainder, number is even, generate a new number until the randomly generated //number is odd. while (random6 % 2 == 0){ random6 = random.nextInt(((cat3 - 2) - (cat2 + 1))) + (cat2 + 1); } //display the question to the user System.out.println("Question: " + myList.get(random6 + 1)); //accept user input System.out.print("Please type your answer: "); //store the user answer in a variable but lowercase answer = scanner.nextLine().toLowerCase(); System.out.println(); //if the user answer matches the official answer, tell them they're correct and award points - else //tell them they are incorrect // Display the officially correct answer from the arraylist String correctAnswer5 = myList.get(random6 +1); System.out.println("Answer: " + correctAnswer5); // Instead use a variable // if the user answer matches the official answer, tell them they're // correct and award points // else tell them they suck LOL if(correctAnswer1.equalsIgnoreCase(answer.trim())) { System.out.println("Correct!"); totalScore = totalScore + awardedPoints; System.out.println("You won " + awardedPoints); } else { System.out.println("Did you even go to school?"); } //display total accumulated points System.out.println("Your total points are: " + totalScore); //wait for user to hit any key before displaying the next question System.out.print("Hit Enter"); System.out.println(""); scanner.nextLine(); } // TODO Auto-generated method stub } </code></pre>
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<java><random><arraylist>
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Create a random within a range from an ArrayList within an Arraylist
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