Searching an array for a course

Question

Here is the algorithm but I am having difficulty with the decipher process :

set flag equal to false
set index equal to 0

WHILE(index is less than number of courses in array AND flag == false)
    extract substring
    IF(string1.equals(string2) == true) THEN //course found
        set flag to true
    ELSE
        increment index
    END IF
END WHILE

IF flag == false THEN
    display message the course name was not found
ELSE
    course name found at position index
END IF

And here is my code:

public void searchCourse(String courseName)
{
    int index;
    String extract;
    boolean notFound = false;
    index = 0;
    while(index < SIZE)
    {
        extract = schedule[index].charAt(0,6);
        if (courseName == extract){

        }
        else {
            index ++;
        }
        if ( notFound == false){
            System.out.println("Course Not Found");
        } 
        else{
            System.out.println("Course Found at: " + index);
        }
    } 
}

Where are you updating notFound value? In your code it's always set to false and it never changes. — Lorenzo Barbagli, May 05 '16 at 21:00
Is ```schedule``` a ```String[]```? ```charAt``` does not have an overload that takes 2 integers. — Jorn Vernee, May 05 '16 at 21:04
Also see: [How do I compare strings in Java?](http://stackoverflow.com/questions/513832/how-do-i-compare-strings-in-java) — Jorn Vernee, May 05 '16 at 21:09
yes schedule is a String[] so should i use .substring(0,6)? @Jorn Vernee — Cuse, May 05 '16 at 21:47

Jorn Vernee · Accepted Answer · 2016-05-05T21:59:11.883

The pseudo code seems needlessly complex.

This will suffice:

public void searchCourse(String courseName) {
    for(int i = 0; i < schedule.length; i++) {
        if(courseName.equals(schedule[i].substring(0, 6))) {
            System.out.println("Course Found at: " + i);
            return;
        }
    }

    System.out.println("Course Not Found");
}

Regardless, a correct translation would look like this:

public void searchCourse(String courseName) {    
    boolean flag = false;
    int index = 0;

    while(index < schedule.length && !flag) {
        String extract = schedule[index].substring(0,6);
        if (courseName.equals(extract)){
            flag = true;
        } else {
            index++;
        }
    }

    if (!flag){
        System.out.println("Course Not Found");
    } else {
        System.out.println("Course Found at: " + index);
    }
}

Thank you for the clarification @John Vernee. – Cuse May 05 '16 at 22:28 — Cuse, May 05 '16 at 22:28

FiReTiTi · Answer 2 · 2016-05-05T22:35:48.050

1

Your code has to be similar as the pseudo-code.

In the pseudo-code, the while loop has two conditions, your code only has one. You use && in java to make a AND, so it becomes && ! notFound
In your first if condition, you have to set the flag to true. It's a simple affectation notFound = true

Btw, the flag should be found instead of notFound, but it does not change anything, except maybe the readability.

edited May 05 '16 at 22:35

answered May 05 '16 at 21:05

FiReTiTi

5,597
12
30
58

That is what I am confused about is how to write the while loop with two conditions do you use a , or a ; to separate index – Cuse May 05 '16 at 21:47
I've upgrade my answer, so you have everything you need to do the two modifications of your code. – FiReTiTi May 05 '16 at 22:33

score 0 · Answer 3 · answered May 05 '16 at 21:33

0

Here correct code

 public void searchCourse(String courseName)
 {
    int index;
    String extract;
    boolean notFound = false;
    index = 0;
    while(index < SIZE)
    {
        notFound = false;
        extract = schedule[index].charAt(0,6);
        if (courseName == extract){
               notFound = true;
        }        
        if ( notFound == false){
            System.out.println("Course Not Found");
        } 
        else{
            System.out.println("Course Found at: " + index);
        }
        index ++;
    } 
}

answered May 05 '16 at 21:33

Sarabala

354
1
3
7

You missed a test in the while loop. So your code goes through all the array instead of stoping asap. – FiReTiTi May 05 '16 at 22:12
And the index has to be incremented only if the string is not found. So your index is going to be greater (just about 1) of what it should be. – FiReTiTi May 05 '16 at 22:32

Searching an array for a course

3 Answers3