What’s wrong with this program?

14y3.5kVisual Basic .NET

This program is producing correct output for "Belt" and "Tie" input. But for the other inputs ("Scarf" and "Cufflinks") program output is "No match found". Anyone can fix the error.

// Debug06-01
// Lists items for sale and their prices
using System;
public class DebugSix01
{
public static void Main()
{
string[] items = { "Belt", "Tie", "Scarf", "Cufflinks"};
double[] prices = { 29.00, 35.95, 18.50, 112.99 };

Console.Write("Items for sale: ");

string enterItem = Console.ReadLine();

int arrayPosition = Array.BinarySearch(items, enterItem);

if (arrayPosition < 0)
Console.WriteLine("No match found");
else
Console.WriteLine("Price {0}", prices[arrayPosition].ToString("c"));

Console.ReadKey();
}
}

2 Replies

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14y ago
Thank you for your explanation.
Vulpes14y ago
The problem is that Array.BinarySearch only works properly if the array is sorted.

As it would be awkward to sort the items array in such a way that the prices array still corresponded, I'd use Array.IndexOf instead:

// Debug06-01
// Lists items for sale and their prices
using System;
public class DebugSix01
{
public static void Main()
{
string[] items = { "Belt", "Tie", "Scarf", "Cufflinks"};
double[] prices = { 29.00, 35.95, 18.50, 112.99 };

Console.Write("Items for sale: ");

string enterItem = Console.ReadLine();

int arrayPosition = Array.IndexOf(items, enterItem);

if (arrayPosition < 0)
Console.WriteLine("No match found");
else
Console.WriteLine("Price {0}", prices[arrayPosition].ToString("c"));

Console.ReadKey();
}
}