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Searching Algorithms

Searching Algorithms

Learn how to perform a linear and binary search in Java.

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Overview

One of the main advantages a computer offers is storing large amounts of data. Computers can find things quicker than humans. This capability is called searching. There are two main types of searching techniques:

  • Sequential search
  • Binary search

Sequential search

Going through all items, one by one, until we find the desired item is called a sequential search. It is also known as a linear search.

For example, if we have the following array, and we need to find 55, we’ll check all the elements one by one.

It’s very easy to code a sequential search in Java. Let’s begin.

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class SequentialSearch 
{
    public static int search(int[] array, int value)
    {
        for(int i = 0; i < array.length; i++)   // Traversing through array
        {
          if(value == array[i])                 // If element found
              return i;
        }
        return -1;                              // Element not found
    }   
    
    public static void main( String args[] ) {
        int[] array = {1, -2, 71, -4, 40, 32};
        // Searching different values
        System.out.println(search(array, -4));
        System.out.println(search(array, 0));
    }
}

Look at line 3. We create the header of the search() function. It takes the array and a value that is to be searched. As a result, it will return the index of the value. If the value isn’t found, it returns −1-1 ...