# C# Program to Estimate the Frequency of the Word “is” in a Sentence

• Last Updated : 18 Oct, 2021

Given a string as input, we need to write a program in C# to count the frequency of the word “is” in the string. The task of the program is to count the number of the occurrence of the given word  “is” in the string and print the number of occurrences of “is”.

Examples:

Input : string = “The most simple way to prepare for interview is to practice on best computer science portal that is GeeksforGeeks”

Output : Occurrences of “is” = 2 Time

Input : string = “is this is the way to talk to your sister? I don’t know what that is”

Output : Occurrences of “is” = 3 Time

Explanation: The “is” has also occurred in the word “sister” and “this” but we are looking for the word “is” to occur separately. Hence only 3 time.

Using Iterative Methods

Approach:

1. Split the string by spaces
2. Store all the words in an array of strings.
3. Now run a loop at 0 to the length of the array of string and check if our string is equal to the word “is”.
4. If the condition is true increment the count else do not increment it.

Code:

## C#

 `// C# program to count the number``// of occurrence of a "is" in``// the given string``using` `System;`` ` `class` `GFG{``     ` `static` `int` `countOccurrencesOfIs(``string` `str)``{``     ` `    ``// Split the string by spaces``    ``string``[] a = str.Split(``' '``);``    ``string` `word = ``"is"``;``     ` `    ``// Search for "is" in string``    ``int` `count = 0;``    ``for``(``int` `i = 0; i < a.Length; i++)``    ``{    ``         ` `        ``// If "is" found increase count``        ``if` `(word.Equals(a[i]))``            ``count++;``    ``}``    ``return` `count;``}`` ` `// Driver code``public` `static` `void` `Main()``{``    ``string` `str = ``"is this is the way to talk to your "` `+ ``                 ``"sister? I don't know what that is"``;``    ``Console.Write(countOccurrencesOfIs(str));``}``}`

Output:

`3`

Time Complexity: O(n) where n is the length of the string.

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