Pseudocode Examples of Basic Search Algorithms

Here are the pseudocode examples for the two most fundamental array search algorithms: Linear Search and Binary Search.

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1. Linear Search Pseudocode

Linear search checks each element one by one from the beginning to the end of the collection.

Function LinearSearch(array, target):
    // Loop through every element in the array
    For i from 0 to length(array) - 1:
        // Check if the current element matches the target
        If array[i] == target Then
            Return i  // Return the index where the target was found
        End If
    End For
    
    // If the loop finishes without finding the target, return -1 (not found)
    Return -1
End Function

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2. Binary Search Pseudocode

Binary search requires a sorted array. It repeatedly divides the search interval in half.

Function BinarySearch(sortedArray, target):
    left = 0
    right = length(sortedArray) - 1
    
    While left <= right:
        // Find the middle index
        mid = left + floor((right - left) / 2)
        
        // Check if target is present at mid
        If sortedArray[mid] == target Then
            Return mid
        
        // If target is greater, ignore the left half
        Else If sortedArray[mid] < target Then
            left = mid + 1
            
        // If target is smaller, ignore the right half
        Else
            right = mid - 1
        End If
    End While
    
    // Target was not present in the array
    Return -1
End Function

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