Java Returning a Correctly Sized Array for Dive Moves

[testme]

If I have a program where I need to return an array, is it possible that I only return the array with the length of what was added to it?

What I mean is I have an array that gets filled up with letters but it doesn't always get completely filled up.

Is there a way I can only return the filled up part (including having only it's size)

Ex: array[4] = {?, ?, ?, ?, ?}

fills up to array[4] = {F, B, F, G,?}

and when I return it I only want an array like this

arr[3] = {F, B, F, G}

 

[Mark44]

If I have a program where I need to return an array, is it possible that I only return the array with the length of what was added to it?

It's hard to answer your question without knowing what language you are writing code in.

What I mean is I have an array that gets filled up with letters but it doesn't always get completely filled up.

Is there a way I can only return the filled up part (including having only it's size)

Ex: array[4] = {?, ?, ?, ?, ?}

Why do you have 5 question marks in an array that has 4 elements?

fills up to array[4] = {F, B, F, G,?}

and when I return it I only want an array like this

arr[3] = {F, B, F, G}

 

[testme]

Oops, sorry, it's late at night here. I'm using Java and bump those up 1. I was thinking as though I'm reading an element from the array.

 

[gabbagabbahey]

If I have a program where I need to return an array, is it possible that I only return the array with the length of what was added to it?

What I mean is I have an array that gets filled up with letters but it doesn't always get completely filled up.

Is there a way I can only return the filled up part (including having only it's size)

Ex: array[4] = {?, ?, ?, ?, ?}

fills up to array[4] = {F, B, F, G,?}

and when I return it I only want an array like this

arr[3] = {F, B, F, G}

Possible, yes (see below, for example). Sensible, probably not. Why work with arrays of Letters instead of a String? What exactly are you trying to do?

import java.util.Arrays;

public class ArrayTest {

	public static void main(String[] args) {
		char[] testArray = {'F', 'B', 'F', 'G','?'};
		char[] filledArray = getFilledArray(testArray);
		for(char c : filledArray) {
			System.out.println(c);
		}
	}
	
	private static char[] getFilledArray(char[] inputArray) {
		String str = Arrays.toString(inputArray);
		str = str.replaceAll("[\\[\\]? ,]", "");
		char[] outputArray = str.toCharArray();
		return outputArray;
	}
	
}

 

[chiro]

Is the size of this object determined at run-time or known before hand?

 

[testme]

Here is my program so you can see what I need. This program is supposed to check if a person dives on a diving board or doesn't because of their nerves. Every step they take is 2 feet and they have to move 10 feet to dive. If they have nerves and step back they move back 2 feet.

/**
 * This program will determine whether a person will dive or not using
 * the probability of someone to jump due to nerves
 */

class Dive 
{
  public static void main (String args[ ])
  {
    // DECLARE VARIABLES/DATA DICTIONARY
    int tMax; //the maximum number of seconds the diver has to dive
    char[] moves; //reference to a character array showing the sequence of man’s moves
    int num; //the number of seconds taken by the diver to dive
    char again; //the character that will determine whether  the user wants to run another trial

    System.out.println("Diving Chance");
    do
    {
    System.out.println("Please enter the maximum time in seconds to make a dive: ");  
    
    // READ IN GIVENS use our ITI1120 special class for keyboard input 
    tMax = ITI1120.readInt(); //reads in the user's choice
    
    // BODY OF ALGORITHM - Call to the method to solve problem
    moves = dive(tMax); //call to the method
    num = moves.length; //gets the length of the array and removes 1 
    
    // PRINT OUT RESULTS AND MODIFIEDS
    if(moves[num - 1] == 'D') //checks to see if the man dived or not
    {
      System.out.print("The man jumped with the moves ");
      for(int i = 0; i < num; i++) //loop that goes through the array of moves and prints each letter out
      {
      System.out.print(moves[i]);
      }
      System.out.println(" in "+num+" seconds");
    }
    /*else
    {
      System.out.print("The man lost his nerves after the moves ");
      for(int i = 0; i < num; i++) //loop that goes through the array of moves and prints each letter out
      {
      System.out.print(moves[i]);
      }
      System.out.println();
    }*/
    System.out.println("Do you wish to make another dive attempt? (y/n): ");
    again = ITI1120.readChar(); //reads in user's input for starting another run
    if(again == 'n')
    {
      System.out.println("Program terminated!");
    }
    }while(again == 'y');
  }
  
  // Problem Solving Method
  // Description: Determines if the man dives or not
  // Parameters (GIVENS): 
  //    tMax - the maximum number of seconds the diver has to dive
  public static char[] dive(int tMax)
  {  
    // DECLARE VARIABLES/DATA DICTIONARY
    
    // INTERMEDIATES
    int x = 0; //the man's distance in feet
    int index = 0; //the index number for the element in the array
    double p; //the probability of taking a step forward
    double ranNum; //a random number
    
    // RESULT
    char diveRes[] = new char[tMax]; //an array that holds the moves takens, F - foward, B - backward, D - dive
    
    // BODY OF ALGORITHM
    while(index < tMax && x < 10) //keeps going as long we haven't exceeded the maximum time allowed or the man hasn't dived
    {
      ranNum = Math.random(); //creates the random number from 0.0 to 1.0
      p = 1.0 - (x/10.0); //calculates the probability 
      if(ranNum < p)
      {
        x = x + 2;
        diveRes[index] = 'F';
      }
      else
      {
        if(x != 0)
        {
        x = x - 2;
        }
        diveRes[index] = 'B';
      }
      index++;
    }
    if(x == 10) //sets the last element in the array to D if the man dives
    {
      diveRes[index - 1] = 'D';
    }
    // RETURN RESULT
   return diveRes;
  }
  
} // Don't remove this brace bracket!

Where my problem lies is in the main method where I'm checking if moves[num-1] == 'D' because num is getting the length of the full array which has a bunch of garbage at the end so it doesn't know that the last letter really was a D.

We were also told we're not allowed to use strings.

 

[gabbagabbahey]

Here is my program so you can see what I need. This program is supposed to check if a person dives on a diving board or doesn't because of their nerves. Every step they take is 2 feet and they have to move 10 feet to dive. If they have nerves and step back they move back 2 feet.

/**
 * This program will determine whether a person will dive or not using
 * the probability of someone to jump due to nerves
 */

class Dive 
{
  public static void main (String args[ ])
  {
    // DECLARE VARIABLES/DATA DICTIONARY
    int tMax; //the maximum number of seconds the diver has to dive
    char[] moves; //reference to a character array showing the sequence of man’s moves
    int num; //the number of seconds taken by the diver to dive
    char again; //the character that will determine whether  the user wants to run another trial

    System.out.println("Diving Chance");
    do
    {
    System.out.println("Please enter the maximum time in seconds to make a dive: ");  
    
    // READ IN GIVENS use our ITI1120 special class for keyboard input 
    tMax = ITI1120.readInt(); //reads in the user's choice
    
    // BODY OF ALGORITHM - Call to the method to solve problem
    moves = dive(tMax); //call to the method
    num = moves.length; //gets the length of the array and removes 1 
    
    // PRINT OUT RESULTS AND MODIFIEDS
    if(moves[num - 1] == 'D') //checks to see if the man dived or not
    {
      System.out.print("The man jumped with the moves ");
      for(int i = 0; i < num; i++) //loop that goes through the array of moves and prints each letter out
      {
      System.out.print(moves[i]);
      }
      System.out.println(" in "+num+" seconds");
    }
    /*else
    {
      System.out.print("The man lost his nerves after the moves ");
      for(int i = 0; i < num; i++) //loop that goes through the array of moves and prints each letter out
      {
      System.out.print(moves[i]);
      }
      System.out.println();
    }*/
    System.out.println("Do you wish to make another dive attempt? (y/n): ");
    again = ITI1120.readChar(); //reads in user's input for starting another run
    if(again == 'n')
    {
      System.out.println("Program terminated!");
    }
    }while(again == 'y');
  }
  
  // Problem Solving Method
  // Description: Determines if the man dives or not
  // Parameters (GIVENS): 
  //    tMax - the maximum number of seconds the diver has to dive
  public static char[] dive(int tMax)
  {  
    // DECLARE VARIABLES/DATA DICTIONARY
    
    // INTERMEDIATES
    int x = 0; //the man's distance in feet
    int index = 0; //the index number for the element in the array
    double p; //the probability of taking a step forward
    double ranNum; //a random number
    
    // RESULT
    char diveRes[] = new char[tMax]; //an array that holds the moves takens, F - foward, B - backward, D - dive
    
    // BODY OF ALGORITHM
    while(index < tMax && x < 10) //keeps going as long we haven't exceeded the maximum time allowed or the man hasn't dived
    {
      ranNum = Math.random(); //creates the random number from 0.0 to 1.0
      p = 1.0 - (x/10.0); //calculates the probability 
      if(ranNum < p)
      {
        x = x + 2;
        diveRes[index] = 'F';
      }
      else
      {
        if(x != 0)
        {
        x = x - 2;
        }
        diveRes[index] = 'B';
      }
      index++;
    }
    if(x == 10) //sets the last element in the array to D if the man dives
    {
      diveRes[index - 1] = 'D';
    }
    // RETURN RESULT
   return diveRes;
  }
  
} // Don't remove this brace bracket!

Where my problem lies is in the main method where I'm checking if moves[num-1] == 'D' because num is getting the length of the full array which has a bunch of garbage at the end so it doesn't know that the last letter really was a D.

We were also told we're not allowed to use strings.

This sounds like a homework problem. Progamming homework questions should be posted in the Engineering, Comp Sci, and Technology homework subforum.

What was the original programming assignment? Have you tried using a simple while loop to find the last letter in your moves array? Have you tried returning a correctly sized array from your dive method? (Right before your return statement, what will the value of index be? Do you see how you can use this to define a new array of the correct size and copy over the letters from diveRes to it, and then return it instead of
diveRes?)