C# | Check if a Stack contains an element

Stack represents a last-in, first out collection of object.
Stack<T>.Contains(Object) Method is used to check whether an element is in the Stack<T> or not.

Syntax:

public virtual bool Contains(object obj);

Return Value: The function returns True if the element exists in the Stack<T> and returns False if the element doesn’t exist in the Stack.

Below given are some examples to understand the implementation in a better way:

Example 1:

// C# code to Check if a Stack
// contains an element
using System;
using System.Collections.Generic;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a Stack of strings
        Stack<string> myStack = new Stack<string>();

        // Inserting the elements into the Stack
        myStack.Push("Geeks");
        myStack.Push("Geeks Classes");
        myStack.Push("Noida");
        myStack.Push("Data Structures");
        myStack.Push("GeeksforGeeks");

        // Checking whether the element is
        // present in the Stack or not
        // The function returns True if the
        // element is present in the Stack, else
        // returns False
        Console.WriteLine(myStack.Contains("GeeksforGeeks"));
    }
}

Output:

True

Example 2:

// C# code to Check if a Stack
// contains an element
using System;
using System.Collections.Generic;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a Stack of Integers
        Stack<int> myStack = new Stack<int>();

        // Inserting the elements into the Stack
        myStack.Push(5);
        myStack.Push(10);
        myStack.Push(15);
        myStack.Push(20);
        myStack.Push(25);

        // Checking whether the element is
        // present in the Stack or not
        // The function returns True if the
        // element is present in the Stack, else
        // returns False
        Console.WriteLine(myStack.Contains(7));
    }
}

Output:

False

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.stack.contains?view=netframework-4.7.2