Daz
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So, I just started learning java this quarter and I'm doing some really simple stuff, however, I've come across something that I cant' find in the lecture slides or in the book.
I need to be able to print this out:
Enter your birthday (mm/dd/yyyy): 10/25/1983
You were born on 25-10-1983
The user input is in bold.
What am I missing here?!
Daz
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Ok, so, onto another problem. I have another simple program that will allow people to put in a number, then put in another, then answer some math questions about it. When they finish answering, it displays a message for them, tells them how many they got correct, and tells them their percentage correct.
My main issues are:
1. When it tells them how many they got correct, it gives 1.0, 2.0, 3.0 etc. instead of 1, 2, 3. I know this has to do with int and double, but I can't figure out how to make them convert neatly (or at all).
2. When it gives them a percentage, I need it to round to five decimal places. I'm not sure how to do this at all.
Anybody know what's up?
Here is my code:
import javax.swing.JOptionPane;
public class Lab3Part2 {
public static void main(String[] args) {
String input;
int firstInt, secInt, productInt, quotientInt, remainderInt, answerInt1, answerInt2, answerInt3;
double score1, score2, score3, totalScore, totalAvg, percentage;
input = JOptionPane.showInputDialog("Please enter an integer.");
firstInt = Integer.parseInt(input);
input = JOptionPane.showInputDialog("Please enter another integer.");
secInt = Integer.parseInt(input);
productInt = firstInt * secInt;
quotientInt = firstInt / secInt;
remainderInt = firstInt % secInt;
JOptionPane.showMessageDialog(null, "Answer the following questions: ");
input = JOptionPane.showInputDialog("1. " + firstInt + " * " + secInt + " = ?");
answerInt1 = Integer.parseInt(input);
if (answerInt1 == productInt) {
JOptionPane.showMessageDialog(null, "Correct.");
score1 = 1;
}
else {
JOptionPane.showMessageDialog(null, "Wrong!");
score1 = 0;
}
input = JOptionPane.showInputDialog("2. " + firstInt + " / " + secInt + " = ?");
answerInt2 = Integer.parseInt(input);
if (answerInt2 == quotientInt) {
JOptionPane.showMessageDialog(null, "Correct.");
score2 = 1;
}
else {
JOptionPane.showMessageDialog(null, "Wrong!");
score2 = 0;
}
input = JOptionPane.showInputDialog("3. " + firstInt + " % " + secInt + " = ?");
answerInt3 = Integer.parseInt(input);
if (answerInt3 == remainderInt) {
JOptionPane.showMessageDialog(null, "Correct.");
score3 = 1;
}
else {
JOptionPane.showMessageDialog(null, "Wrong!");
score3 = 0;
}
totalAvg = (score1 + score2 + score3) / 3;
totalScore = (score1 + score2 + score3);
if (totalAvg == 0) {
JOptionPane.showMessageDialog(null, "You did very bad.");
}
else if (totalAvg > .33 && totalAvg < .66) {
JOptionPane.showMessageDialog(null, "You did poorly.");
}
else if (totalAvg >= .66 && totalAvg < 1) {
JOptionPane.showMessageDialog(null, "You did OK.");
}
else if (totalAvg == 1) {
JOptionPane.showMessageDialog(null, "Good Job!");
}
JOptionPane.showMessageDialog(null, "You got " + totalScore + " correct.");
percentage = totalAvg * 100;
JOptionPane.showMessageDialog(null, "That's " + percentage + "%");
System.exit(0);
}
}
hobbesOSU
West Side C-bus
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YMMV, but I would use Integer and Double and not the primitives int and double. If you want to use primitives, you'll probably have to cast them.
ie
JOptionPane.showMessageDialog(null, "You got " + totalScore + " correct.");
might be
JOptionPane.showMessageDialog(null, "You got " + (int) totalScore + " correct.");
To figure out your percentage, this code snip might help you:
double d = 1.234567;
DecimalFormat df = new DecimalFormat("#.##");
System.out.print(df.format(d));
myliftkk
Columbus, OH
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Here is a functionally identical, but much more ideally structured bit of code without solving your format issue.
import javax.swing.JOptionPane;
public class TestClass {
public static void main(String[] args) {
int firstInt, secInt;
double score=0, totalAvg;
firstInt = getInput("Please enter an integer.");
secInt = getInput("Please enter another integer.");
showMessage("Answer the following questions: ");
if(compare(getInput("1. " + firstInt + " * " + secInt + " = ?"), firstInt * secInt))
score++;
if(compare(getInput("2. " + firstInt + " / " + secInt + " = ?"),firstInt / secInt))
score++;
if(compare(getInput("3. " + firstInt + " % " + secInt + " = ?"),firstInt % secInt))
score++;
totalAvg = score/3;
if (totalAvg == 0)
showMessage("You did very bad.");
else if (totalAvg < .66)
showMessage("You did poorly.");
else if (totalAvg < 1)
showMessage("You did OK.");
else
showMessage("Good Job!");
showMessage("You got " + score + " correct.");
showMessage("That's " + totalAvg * 100 + "%");
System.exit(0);
}
public static int getInput(String m) {
return Integer.parseInt(JOptionPane.showInputDialog(m));
}
public static void showMessage(String m) {
JOptionPane.showMessageDialog(null, m);
}
public static boolean compare(int i1, int i2) {
if (i1 == i2)
{
showMessage("Correct.");
return true;
}
showMessage("Wrong!");
return false;
}
}
Java has a large number of format classes such as NumberFormat that you can use to make sure your output for display fits a particular format requirement. What you need to do is look up some of those classes in the Javadoc and you should find the answer you are looking for.
Daz
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I swear I have learned more about java by the couple of suggestions in this thread than I have learned in the last week of class.
Thank you.
I'll see what's allowed as far as my instructors are concerned with me going above and beyond what has been taught so far.
Daz
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Here's this week's lab:
I feel so overwhelmed.
Here is a sample interaction between a user and the program you will write in the Lab6 class (user inputs are in bold):
How many numbers? [b]100[/b]
How many intervals? [b]10[/b]
Histogram
--------------------------------------------------------
1 ****(4)
2 ******(6)
3 ***********(11)
4 *****************(17)
5 **************************(26)
6 *************************(25)
7 *******(7)
8 ***(3)
9 (0)
10 *(1)
--------------------------------------------------------
The program performs the following actions:
1. Ask the user to enter the number of numbers that will be generated and the number of intervals that will be used in the histogram, and input the two values;
2. Generate the required number of pseudo-random numbers by using the double[] Generator.getData(int n), which, given the number of numbers to generate, n, returns an array of double of size n containing the generated numbers;
3. Compute the range of data values (by finding the maximum and the minimum and taking their difference); then compute the width of each equally-sized interval (by dividing the whole range by the number of intervals specified by the user); finally, compute the number of data numbers falling in each interval and store these frequencies in an array of integers;
4. Output the histogram of the data as displayed in the sample run above: each bar starts with an index (1 through the number of intervals), followed by a number of '*' equal to the number of numbers in that range, followed by the number of '*' in parentheses.
Note: Pay attention to detail. Make your output look like the output in the sample run. However, note that your program must be able to produce the correct histogram for arbitrary data, not just for the specific data generated by Generator.getData().
Daz
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Here's where I am so far:
import javax.swing.JOptionPane;
public class Lab6 {
public static void main(String[] args) {
String input1, input2;
int howManyNumbers, howManyIntervals;
double max, mini, range, widthOfIntervals;
/* Ask the user to enter the number of numbers that
will be generated and the number of intervals that
will be used in the histogram, and input the two values;*/
input1 = JOptionPane.showInputDialog("How Many Numbers?");
howManyNumbers = Integer.parseInt(input1);
input2 = JOptionPane.showInputDialog("How Many Intervals?");
howManyIntervals = Integer.parseInt(input2);
/*Generate the required number of pseudo-random numbers by
* using the double[] Generator.getData(int n),
* which, given the number of numbers to generate, n, returns
* an array of double of size n containing the generated numbers;*/
double [] generated = new double[howManyNumbers];
generated = randomGenerator(howManyNumbers);
/*# Compute the range of data values (by finding the maximum and the minimum and
* taking their difference); then compute the width of each equally-sized
* interval (by dividing the whole range by the number of intervals specified by the user);
* finally, compute the number of data numbers falling in each interval
* and store these frequencies in an array of integers; */
max = maximum(generated);
mini = minimum(generated);
range = max - mini;
widthOfIntervals = range / howManyIntervals;
}
private static double [] randomGenerator(int number) {
double [] generate;
generate = Generator.getData(number);
return generate;
}
private static double maximum(double [] a) {
double max = a[0];
for (int i = 1; i < a.length; i++) {
if (a[i] > max) {
max = a[i];
}
}
return max;
}
private static double minimum(double [] a) {
double mini = a[0];
for (int i = 1; i < a.length; i++) {
if (a[i] < mini) {
mini = a[i];
}
}
return mini;
}
}
myliftkk
Columbus, OH
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Daz wrote Here's where I am so far:
import javax.swing.JOptionPane;public class Lab6 {
public static void main(String[] args) {
String input1, input2;
int howManyNumbers, howManyIntervals;
double max, mini, range, widthOfIntervals;
/* Ask the user to enter the number of numbers that
will be generated and the number of intervals that
will be used in the histogram, and input the two values;*/
input1 = JOptionPane.showInputDialog("How Many Numbers?");
howManyNumbers = Integer.parseInt(input1);
input2 = JOptionPane.showInputDialog("How Many Intervals?");
howManyIntervals = Integer.parseInt(input2);
/*Generate the required number of pseudo-random numbers by
* using the double[] Generator.getData(int n),
* which, given the number of numbers to generate, n, returns
* an array of double of size n containing the generated numbers;*/
double [] generated = new double[howManyNumbers];
generated = randomGenerator(howManyNumbers);
/*# Compute the range of data values (by finding the maximum and the minimum and
* taking their difference); then compute the width of each equally-sized
* interval (by dividing the whole range by the number of intervals specified by the user);
* finally, compute the number of data numbers falling in each interval
* and store these frequencies in an array of integers; */
max = maximum(generated);
mini = minimum(generated);
range = max - mini;
widthOfIntervals = range / howManyIntervals;
}
private static double [] randomGenerator(int number) {
double [] generate;
generate = Generator.getData(number);
return generate;
}
private static double maximum(double [] a) {
double max = a[0];
for (int i = 1; i < a.length; i++) {
if (a[i] > max) {
max = a[i];
}
}
return max;
}
private static double minimum(double [] a) {
double mini = a[0];
for (int i = 1; i < a.length; i++) {
if (a[i] < mini) {
mini = a[i];
}
}
return mini;
}
}
Are you allowed to create objects of your own yet, or not? Your on the right path, albiet taking a brutally circuituitous route to getting there.
Assuming what you've got works so far, nothing strikes me as out of the ordinary, you just need to tackle the histogram.
Once you've detemined the number of intervals, you can create your intervals. Think of each interval as it's own object with a few key properties and maybe a single method. For example, you could say an interval has two key attributes, a lower bound and a upper bound.
Interval (Class)
-->uppperBound (double)
-->lowerBound (double)
You probably want a constructor that takes a lower and upper bound.
Now you're going to want to create n number of Interval objects, you can store them in an Arraylist or just plain array [] and then process through them using a for() loop.
Once you've got your collection of Interval objects, you'll want to be able to compare a data point to each interval and determine which one it falls in. One way to do this is by creating a method in the Interval class like "isFoundBetween(double d)" that returns true if the data point falls between the object's lower and upper bounds.
You'll need an second array of ints that you'll want to create based off the n specified by the user. That array will hold your counters for each interval. When you find get a "true" return from the method, you tick the proper counter until you've processed all the random data points.
You'll need some for loops for the counting and then some different for loops for the printing. Basically, you need a for loop based off your array of counter to print the 'x's.
If you find this post just shoots over your head like a cruise missile, tell you what, (assuming this isn't due like tomorrow), drop me a note at my corporate email if you're around to work on it tomorrow during work hours (say 9-6pm) with a number and I'll give you a call and probably break it down faster in a conversation than I could ever possibly write.
Isn't Java fun?!?! :wink:
-Scott
th0m
Beechwold
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any of you java types (or any reading) want to collaborate on projects using processing or other java arty type things? http://www.processing.org/
Daz
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what I have as of now, it's coming up with HUGE numbers....:
/* Created By Jeffrey Lembeck
*
* Due November 13, 2007
*
* Lab 6
*/
import java.util.Scanner;
public class Lab6 {
public static void main(String[] args) {
int howManyNumbers, howManyIntervals, widthOfIntervals;
double max, mini, range;
Scanner keyboard = new Scanner(System.in);
/* Ask the user to enter the number of numbers that
will be generated and the number of intervals that
will be used in the histogram, and input the two values;*/
System.out.print("How Many Numbers? ");
howManyNumbers = keyboard.nextInt();
System.out.print("How Many Intervals? ");
howManyIntervals = keyboard.nextInt();
/*Generate the required number of pseudo-random numbers by
* using the double[] Generator.getData(int n),
* which, given the number of numbers to generate, n, returns
* an array of double of size n containing the generated numbers;*/
double [] generated = new double[howManyNumbers];
generated = randomGenerator(howManyNumbers);
/* Compute the range of data values (by finding the maximum and the minimum and
* taking their difference); then compute the width of each equally-sized
* interval (by dividing the whole range by the number of intervals specified by the user);
* finally, compute the number of data numbers falling in each interval
* and store these frequencies in an array of integers; */
max = maximum(generated);
mini = minimum(generated);
range = max - mini;
widthOfIntervals = (int)range / howManyIntervals;
int [] intervalValue = new int[howManyIntervals];
for (int i=0; i < howManyIntervals; i++) {
intervalValue[i] = ((int)generated[i]);
}
System.out.println("Histogram");
System.out.println("--------------------------------" +
"------------------------");
for (int a=0; a < intervalValue.length; a++) {
System.out.print(" " + (a+1) + " ");
for (int b=0; b < intervalValue[a]; b++) {
System.out.print("*");
}
System.out.println("(" + intervalValue[a] + ")");
}
}
private static double [] randomGenerator(int number) {
double [] generate;
generate = Generator.getData(number);
return generate;
}
private static double maximum(double [] a) {
double max = a[0];
for (int i = 1; i < a.length; i++) {
if (a[i] > max) {
max = a[i];
}
}
return max;
}
private static double minimum(double [] a) {
double mini = a[0];
for (int i = 1; i < a.length; i++) {
if (a[i] < mini) {
mini = a[i];
}
}
return mini;
}
}
Schoolboy
Columbus
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i find java only usefull in the real world when it comes to pop up message boxes
rarely if ever use it outside of that
when you get to VB, asp, sql, .net, etc... hit me up
i am even expert level in cl cobol and rpg... doubt any college still teaches that lol
one language that i actually don't use ever is c++
myliftkk
Columbus, OH
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th0m wrote any of you java types (or any reading) want to collaborate on projects using processing or other java arty type things? http://www.processing.org/
If you'd said, Ruby project, I might be interested. A MIT lab language that is "used by students, artists, designers, researchers, and hobbyists", I think I'll have to pass. :wink:
th0m
Beechwold
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here is a link on how to use JRuby with Processing... I'm on the Python side of that fence. ;p But, I dunno... there are a lot of great viz happening in a lot of languages... and there are many libraries...
myliftkk
Columbus, OH
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th0m wrote here is a link on how to use JRuby with Processing... I'm on the Python side of that fence. ;p But, I dunno... there are a lot of great viz happening in a lot of languages... and there are many libraries...
I am a black boxer myself and avoid visuals whenever possible, so I don't have much use for these new libraries languages that focus on the visual. Though they are interesting and at least show growth in that space on the JVM.
Rule engines, unattended processes, financial transaction processors, statistic number crunching, communication/application frameworks, that more the sandboxes I play in, and almost always with Cobol/Java. I leave the glass to people who can tolerate users saying "I don't like the color and size of that text label, could you change it?". Yeah, let me get right on that. :roll:
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