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Thread: how do i make my program to do......

  1. #1
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    Default how do i make my program to do......

    I got stuck while doing my assignment which is to:

    1. Read in all 20 lines of text from a file and store them.
    2. Display all the 20 lines of text on the screen
    3. Display every other line in upper case (so the first, then the third etc), you don’t need to display the other line at all (i.e. no output of second, fourth etc.)
    4. Display the number of characters in each line of text and display the average of the characters for all 20 lines of text.
    5. Display the first 10 characters from each line of text


    I did the first two tasks.....and my code for that is
    import java.util.Scanner;
    import java.io.File;
     
     
    class Displaytext{
     
    	public static void main (String args[])throws Exception {
     
    		String[]text=new String[20];
    		File myfile = new File("alice.txt");
    	    Scanner scan = new Scanner(myfile);
            String alice;
     
     
     
    	  for (int a=0; a<20; a++)
    	    {
     
     
     
    			alice = scan.nextLine();
    			System.out.println(alice);
     
    		}
     
    	    scan.close();
     
    	}
    }

    Can someone help me in altering this so that it does the rest of the tasks........


  2. #2
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    Default Re: how do i make my program to do......

    When posting code, make sure you use the code tags to preserve formatting. Otherwise nobody will read it.

    But as for your other requirements, what have you tried? Hint: You'll probably want to store your Strings in an Array or a List.

  3. #3
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    Default Re: how do i make my program to do......

    A few notes on what you have now. First, please put JAVA tags around your code, it makes it easier to read and ensures faster and better assistance. To figure out how to use JAVA tags, read my signature.

    Second, based on the assignment, I can understand the loop going to 20, but when you use Scanner, you usually want to go until there are no more lines left. OR, at least check to see if the line you are reading in exists. Basically, scan.nextLine(); will return null when the next line doesnt exist. So, there are two ways that this can be done more efficiently. First, if you want to read all of the lines, instead of
    String alice;
     
    for (int a=0; a<20; a++)
    {
    alice = scan.nextLine();
    System.out.println(alice);
    }
    you would want something like:
    String alice = scan.nextLine();
     
    while(alice!=null)
    {
    	System.out.println(alice);
    	alice = scan.nextLine();
    }

    Alternatively, if you want to read only 20 lines, you should put a check in your statement:
    for (int a=0; a<20; a++)
    {
    	alice = scan.nextLine();
    	if(alice==null)
    		break;
    	System.out.println(alice);
    }

    This guarantees you will not continue to read when you reach the end of the file and prevents possible exceptions from being thrown.

    3. Display every other line in upper case (so the first, then the third etc), you don’t need to display the other line at all (i.e. no output of second, fourth etc.)
    4. Display the number of characters in each line of text and display the average of the characters for all 20 lines of text.
    5. Display the first 10 characters from each line of text
    I will tell you how to do all of these, but not give you the code for it. Try to figure out the code based on the directions I give and if you have any trouble with the code, post it and I'll help you debug.
    3. So the first thing we need to do is remember each line when we read it in. I noticed you already made a String[] named text. This is where you want to store your lines of text. So, when you read in the line of text in your loop above, you should also add that line of text to the String array. Then, after you have read in all of the lines, you want to go through the array and get each String that has an even index. Why even? Because the indexes start at 0. So you want to get indexes 0,2,4,6,...16,18. Remember that index #20 does not exist because indexes start at 0 and end at the length of the array minus 1. When you get each String, you want to use the String.toUpperCase() method. Remember that this method returns a String, not replace the String the method was evoked from. So, you simply want to print out the String the method returns.
    4. Now that we have our array of Strings from #3, we can go through the array again. Before looping through the array, you need to declare a variable that will be the total of all the length. Then when you go through each index in the array, use the String.length() method. This method returns an int representing how many characters are in the String. You want to print that value out, but you also want to add that value to our total variable. Lastly, when you exit the loop, you want to divide the total by 20 (since that is the number of Strings we have) and print out that result as well.
    5. Once again, we go through the array of Strings. This time, we use the String.substring(int,int) method. In this method, the first int is the starting index and the second int is the ending index. This method returns a String of just the characters between the indexes you identified. So, you want to get each String in the array, and print out the value of String.substring(0,10);.

    I think that should be everything. Tell me if you have any trouble.
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  4. #4
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    Default Re: how do i make my program to do......

    Quote Originally Posted by aussiemcgr View Post
    A few notes on what you have now. First, please put JAVA tags around your code, it makes it easier to read and ensures faster and better assistance. To figure out how to use JAVA tags, read my signature.

    Second, based on the assignment, I can understand the loop going to 20, but when you use Scanner, you usually want to go until there are no more lines left. OR, at least check to see if the line you are reading in exists. Basically, scan.nextLine(); will return null when the next line doesnt exist. So, there are two ways that this can be done more efficiently. First, if you want to read all of the lines, instead of
    String alice;
     
    for (int a=0; a<20; a++)
    {
    alice = scan.nextLine();
    System.out.println(alice);
    }
    you would want something like:
    String alice = scan.nextLine();
     
    while(alice!=null)
    {
    	System.out.println(alice);
    	alice = scan.nextLine();
    }

    Alternatively, if you want to read only 20 lines, you should put a check in your statement:
    for (int a=0; a<20; a++)
    {
    	alice = scan.nextLine();
    	if(alice==null)
    		break;
    	System.out.println(alice);
    }

    This guarantees you will not continue to read when you reach the end of the file and prevents possible exceptions from being thrown.


    I will tell you how to do all of these, but not give you the code for it. Try to figure out the code based on the directions I give and if you have any trouble with the code, post it and I'll help you debug.
    3. So the first thing we need to do is remember each line when we read it in. I noticed you already made a String[] named text. This is where you want to store your lines of text. So, when you read in the line of text in your loop above, you should also add that line of text to the String array. Then, after you have read in all of the lines, you want to go through the array and get each String that has an even index. Why even? Because the indexes start at 0. So you want to get indexes 0,2,4,6,...16,18. Remember that index #20 does not exist because indexes start at 0 and end at the length of the array minus 1. When you get each String, you want to use the String.toUpperCase() method. Remember that this method returns a String, not replace the String the method was evoked from. So, you simply want to print out the String the method returns.
    4. Now that we have our array of Strings from #3, we can go through the array again. Before looping through the array, you need to declare a variable that will be the total of all the length. Then when you go through each index in the array, use the String.length() method. This method returns an int representing how many characters are in the String. You want to print that value out, but you also want to add that value to our total variable. Lastly, when you exit the loop, you want to divide the total by 20 (since that is the number of Strings we have) and print out that result as well.
    5. Once again, we go through the array of Strings. This time, we use the String.substring(int,int) method. In this method, the first int is the starting index and the second int is the ending index. This method returns a String of just the characters between the indexes you identified. So, you want to get each String in the array, and print out the value of String.substring(0,10);.

    I think that should be everything. Tell me if you have any trouble.

    HEY THANKS VERY MUCH FOR UR HELP.....i got around fine with those tasks.....but can u give me some direction for the following tasks aswell...........i really appreciate ur help

    6. Ask the user for a word to find in the text. Then display all the text in lower case, except for the target word, which should be in upper case. Also display how many times the target word was found.
    7. Modify the code so that it works with a text file of up to 300 lines of text. Your program should handle no lines, one line or any where up to 300 lines.

  5. #5
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    Default Re: how do i make my program to do......

    Quote Originally Posted by andys View Post
    I got stuck while doing my assignment which is to:

    1. Read in all 20 lines of text from a file and store them.
    2. Display all the 20 lines of text on the screen
    3. Display every other line in upper case (so the first, then the third etc), you donít need to display the other line at all (i.e. no output of second, fourth etc.)
    4. Display the number of characters in each line of text and display the average of the characters for all 20 lines of text.
    5. Display the first 10 characters from each line of text


    I did the first two tasks.....and my code for that is

    import java.util.Scanner;
    import java.io.File;


    class Displaytext{

    public static void main (String args[])throws Exception {

    String[]text=new String[20];
    File myfile = new File("alice.txt");
    Scanner scan = new Scanner(myfile);
    String alice;



    for (int a=0; a<20; a++)
    {



    alice = scan.nextLine();
    System.out.println(alice);

    }

    scan.close();

    }
    }

    Can someone help me in altering this so that it does the rest of the tasks........
    Hi its Melanie, sounds like your assignment is not going to well!! Just to let you know, you may wish to take a look at the Academic offences, located on myBu. I have advised Nan (who will be marking the work this week) that any work that is believed to be plagarised, will be marked as 0 with a disiplinary with Ruth.

  6. #6
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    Default Re: how do i make my program to do......

    This thread is also related to - how do i make my program to....
    Please use [highlight=Java] code [/highlight] tags when posting your code.
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    Default Re: how do i make my program to do......

    Quote Originally Posted by MelanieC View Post
    Hi its Melanie, sounds like your assignment is not going to well!! Just to let you know, you may wish to take a look at the Academic offences, located on myBu. I have advised Nan (who will be marking the work this week) that any work that is believed to be plagarised, will be marked as 0 with a disiplinary with Ruth.
    Please be careful not to break any rules. It looks like your University are monitoring students on this forum.
    Try to complete as much of the code as possible and we will point you in the right direction when you are stuck..
    Please use [highlight=Java] code [/highlight] tags when posting your code.
    Forum Tip: Add to peoples reputation by clicking the button on their useful posts.

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