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Question

I have a list of numbers and I am trying to find the numbers "58" and "85" in this list. It should print True if it is the number, and False otherwise. I have just been trying to get the 58 part so far. When I run the program, all it prints is "True 58" Is there something wrong with my else statement? I can't seem to find the problem.

import java.util.Arrays;


public class asgn9
{
    public static void main(String[] args)
    {
        int[] data = { 12, 25, 35, 45, 58, 64, 77, 80, 84, 93 };
        int searchedValue = 58;
        int searchedValue2 = 85;

        keyTest(data, searchedValue, searchedValue2);
    }

    public static void keyTest(int[] data, int searchedValue, int searchedValue2)
    {
        boolean found = false; 
        int low = 0;
        int high = data.length - 1;
        int pos = 0;

        while (low <= high && !found)
        {
            pos = (low + high) / 2; // Midpoint of the subsequence
            if (data[pos] == searchedValue) 
            { found = true; }    
            if (data[pos] < searchedValue) 
            { low = pos + 1; }      // Look in first half
            else
            { high = pos - 1; }     // Look in second half
        }
        if (found = false)
            System.out.println("False " + data[pos]);
        else if (found = true)
            System.out.println("True " + data[pos]);
    }//end of keyTest
}

Edit:

I used a for loop and now I am getting the 10 lines I should be. Each line is returning "True 58." I also tried editing statements in the actual search, however I'm not sure if they are necessary.

for (i = 0; i < data.length; i++)
    {

    while (low <= high && !found)
    {
      pos = (low + high) / 2;  // Midpoint of the subsequence
      if (data[pos] == searchedValue) 
        { found = true; }    
         else { found = false;}
        { low = pos + 1; }     // Look in first half
         if (data[pos] == searchedValue)
         {found = true;}
         else { high = pos - 1; }// Look in second half
         if (data[pos] == searchedValue)
         {found = true;}
         else { found = false;}

    }

    if (!found)
    System.out.println("False " + data[pos]);
    else
    System.out.println("True " + data[pos]);

    }//end of for

Answer 1

One = is assignment (and then you test the value assigned as a side-effect). You need two == like

if (found == false) {
    System.out.println("False " + data[pos]);
} else if (found == true) {
    System.out.println("True " + data[pos]);
}

Also, I'd prefer the shorter boolean not ! like

if (!found) {
    System.out.println("False " + data[pos]);
} else {
    System.out.println("True " + data[pos]);
}

Answer 2

You're using single equal signs in your tests which means that you're assigning values and then testing them.

Your code is equal to this:

    if (false)
        System.out.println("False " + data[pos]);
    else if (true)
        System.out.println("True " + data[pos]);

Use double equal signs for comparison:

    if (found == false)
        System.out.println("False " + data[pos]);
    else if (found == true)
        System.out.println("True " + data[pos]);

And since found can only be either true or false you can shorten it to:

    if (found == false)
        System.out.println("False " + data[pos]);
    else
        System.out.println("True " + data[pos]);

Answer 3

You are using = which is assigning operator, which means

found = false will assign the value `false` to found so it is not going to `false`

you should use == for condition check.

Since your found flag is boolean , you should try the following code

 if (!found)
            System.out.println("False " + data[pos]);
 else if (found)
            System.out.println("True " + data[pos]);
    }//end of keyTes