Need help with computing the total number

[Joan Tan]

For example, a user input a number of country into a queue such as Iceland, Italy, Spain,Switzerland and Singapore . How do I compute the total number of country name that begins with the same letter?
The outcome should be
Total number of countries start with I : 2
Total number of countries start with S : 3

public class CityTravelerApp {
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
// TODO code application logic here
Queue myQueue= new Queue(80);
System.out.println("Welcome to the Traveler Application!" );
//a. Generate a random number called num between 1 and 10, inclusive.
Random number = new Random();
int value = number.nextInt(10)+1;
System.out.println("The random number generated is " +value +".");
//b. Prompt the user to enter the names of the countries and add the names to a queue on a first-come-first-served basis.
for(int i =1;i<=value ;i++){
System.out.println("Enter the name of country #" + i+":");
String name = input.next();
myQueue.enqueue(name);
}
//c. After all the countries have been entered, your program should dequeue the list of visited countries and print them out, one at a time.
System.out.println("List of countries visited: ");
for(int j=1; j <=value; j++){
System.out.println(j+". " +(myQueue.dequeue()));
}
//d. Print the total number of country names in the queue that begins with the same letter.
//e. To compute the above statistics you may use other data structures, such as Array, or ArrayList/Vector.
System.out.println("Statistics:");
Array count = new Array(); // This is the part I'm stucked at.
}
}

[Campbell Ritchie]

If you look in the Java™ Tutorials, you will find an example of counting words. You should be able to amend that to map first letter ↦ count.

[Campbell Ritchie]

I think you should move 99% of that code out of the main method.

[Liutauras Vilda]

Welcome to the Ranch.

Probably would be better if you wouldn't cram all code into main method, but instead create appropriately named method for your each task, so you wouldn't need write such long comments.

Joan Tan wrote:How do I compute the total number of country name that begins with the same letter?

Have you tried with charAt or substring methods? Might one of these would work.

[Scott Bee]

Hi, Joan --

It is definitely wise to start with Campbell and Liutauras's advice to break this problem down into tasks, then code each task in its own method. If you were doing this by hand, how would you summarize the broad steps? For example, if I were to try to encode my process of responding to this post, I might have methods that look like...

public void readForumPost() {
// Load forum post content and replies into brain memory.
... code goes here ...
}
public boolean canIRespondHelpfully() {
// Evaluate contents of posts and replies to date. Return true if I can add something useful, false otherwise.
... code goes here ...
}
public String composeResponse() {
// Create the text of my response. Return a String containing response text.
... code goes here ...
}
public void postResponse(String response) {
// Complete the process of posting the response to the forum.
... code goes here ...
}

Then my main() method looks like this...

public class ForumReaderResponder {
public static void main(String[] args) {
ForumReaderResponder readerResponder = new ForumReaderResponder(); // Initialize class
readerResponder.readForumPost();
if (readerResponder.canIRespondHelpfully()) {
String response = readerResponder.composeResponse();
readerResponder.postResponse(response);
}
}
// Rest of methods (described above) go here...

I know I'm over-explaining this, but it's a good practice start with this type of logical breakdown.

By the way, I illustrated this using Java code, but it is far more important that you do this kind of breakdown on paper, before you start coding.

Then, once you've figured out the logic on paper, you can try encoding each method, one step at a time. What I'm responding to (and maybe Campbell and Liutauras feel similarly) is that there are a number of issues with your draft code, starting all the way back at line 10 (or even earlier if you're missing necessary import statements). Once you've broken this down, you can get help on each piece.

--Scott

[Paweł Baczyński]

Scott, that is a great example. Have a cow!

[Scott Bee]

 

Paweł Baczyński wrote:Have a cow!

Thank you, Pawel!