String Length in C
In C, a string is an array of characters that is terminated with a null character "\0" . The length of a string will be determined by counting all the characters in the string (except for the null character) .
Scope of Article
- In this article, we will learn to find the length of a String in C.
- All the methods to find the length of a String will be explained in this article.
- Every method will be explained using syntax, images, and examples.
Introduction
The string length in C is equal to the count of all the characters in it (except the null character "\0").
For Example, the string "gfddf" has a length of 5 and the string "4343" has a length of 4 .
Note: In C, a String is an array of characters that is terminated with a null character "\0" to indicate the end of the string.
How to Find the String Length in C?
We can find the length of a String by counting all the characters in it (before the null character) using a for loop. We can also use the built-in string.h library function strlen() or the sizeof() operator.
Let us understand how to use these methods in the coming sections.
String Length in C using a User-Defined Function
We can find the length of a string using a user-defined function by iterating over the string in a for loop and incrementing the count of characters (length) by 1 till it reaches the null character "\0" and then returning the count.
Let's take a look at its implementation:
Code
Output
Explanation:
In the above example, we are finding the length of a string by iterating over it in a for loop and incrementing the count by 1 in each iteration till it reaches the null character. The value of count after the end of the for loop will be equal to the length of the string.
String Length in C Using Built-In Library Function
The length of a string can be found using the built-in library function strlen() in string.h header file. It returns the length of the string passed to it (ignoring the null character).
Syntax
The string is passed to the strlen() function, which returns its length.
Let us take a look at its implementation.
Code
Output :
In the above example, we are finding the length of a string by using the string.h library function strlen() , which returns the length of the string passed to it.
String Length in C Using the sizeof() Operator
We can also find the length of a string using the sizeof() Operator in C . The sizeof is a unary operator which returns the size of an entity (variable or value).
The value is written with the sizeof operator which returns its size (in bytes).
Let us take a look at its implementation:
Code
Output
In the above example, we are finding the length of the string "g4343" using the sizeof operator in C. The sizeof operator returns its length as 6 in the output as It returns the size of an operand, not the string length (including null values). But here, if we print length-1 then we get the length of the string.
C# String Length: How to use it?
To get the string length in C#, use the .Length property.
Examples
What is String Length in C#?
String Length in C# is a property on the String object that returns the number of characters in a string. The returned length value is of type Int32.
The Length property of a string is the number of Char objects it contains, not the number of Unicode characters.
The length property returns the number of Char objects instead of the number of Unicode characters because a Unicode character might be represented by more than one character.
What is the max string length in C#?
The maximum string length in C# is 2^31 characters. That's because String.Length is a 32-bit integer.
How to change string length in C#?
You can't change the string length in C#. The String.Length property is read-only.
To change the string length, you need to create a new string.
If you try to change the Length property, you will get an error:
How to access each Unicode character?
To access each Unicode character in a C# string, you use the System.Globalization.StringInfo class to work with each Unicode character instead of each character.
Exception
One of the most frequent null-reference exceptions is with String.Length property.
If you try to access the Length property on a null string, you will get a NullReferenceException.
Many developers forget to check for null before accessing the Length property.
Index vs Length
In C#, string length returns the number of characters in a string.
The index property returns the zero-based position of the character that is located at a specified location within an instance of String.
The length property doesn't start at 0. It starts at the first character in the string. But the index property starts at 0.
Under the hood
Internally, C# stores strings as a read-only collection of Char objects. There's also a null-terminating character at the end of a C# string.
C# doesn't count the null-terminating character in the length of a string. The null-character is just a way C# marks the end of a string under the hood.
Termination
Programming languages have different approaches to determine the string end:
- Null-terminated — Strings in C are null-terminated sequences of characters, with a special character following the last character—written "\0" — to show the end of the string.
- Length-prefixed -Pascal stores the length in the first bytes of the string.
- Length-and-Character Array — String as a structure with an array of characters, and stores the length in a separate allocation.
Changes in length
Programming languages have different approaches to handle changes in string length:
- Static string length is fixed and cannot be changed at runtime.
- Limited Dynamic string length can be increased or decreased, but the number of characters that can be stored in it is limited.
- Dynamic string length can grow or shrink as needed, up to the maximum size allowed by the underlying system.
In C#, strings have dynamic string length. It means that the string can grow or shrink as needed.
String class
The String class holds the implementation details and the string manipulation functionality. Looking at the source code, we can see that the string length is crucial for the string class.
Как узнать количество символов в строке на C#?
Как в коде можно реализовать подсчет количества символов в строке? Я смотрел на MSDN -> класс String , вроде бы не нашел ничего похожего.
Наверное у вас другая MSDN.
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C# String Length
In this syntax, we see that we declare an integer “int” with any name of our choice and assign the string length to this integer value by using our “str_name.Length”.
Example # 1: Calculating string length using the Built-in method
In the given example, we are going to calculate the length of the string which is given in the C# program in Ubuntu 20.04. You must write the given code on your text editor. We are performing this example on Ubuntu 20.04 text editor. You must have saved this file after completing this code with the extension of “.cs”.
In this given code, we are importing the “using System” library. You can define many resources in a single line with the help of the “using” statement. The “using System” is used in the C# program for accessing functions and methods that are used in this C# program. Now, we are using the namespace in the next line. The namespace is named “stringLength” in this code. Then, we are declaring a class with the name “CSharp” here. Inside this class, we invoked a function which is the main function of the C# program.
Here, “static void Main(String[ ] args)” is the main method of this program. This “main” function is static and “(String [ ] args) is used here for the arguments in this “main” function. The “main” function is used for the execution of the code which is written inside the “main” method. Inside the curly braces of this “main” method, we are declaring a string with a name “S” and then assign a string character to that string. Here in this code, we assign “aeiou” to this string. We want to calculate the length of this given string. For this, we use the syntax of string length which we described above.
We are declaring integers as “int” with a name “leng” and assign “string_name. Length” to this integer. Now “S.Length” is assigned to “int leng” in this code, which will calculate the character including spaces in this string. Here, we have no space in this string. After all this, it’s the time to print or display the string length on the screen and for this, we are using “Console.WriteLine” which prints all data which is written inside it. We are displaying the string length here with the help of this “Console.WriteLine”.
For displaying the output in Ubuntu 20.04 terminal, we have the commands which are given here. Now, have a look at these commands, so that you can easily get the output using these commands. First, we are using the “mcs” command and “strleng” is the filename here with the extension of “.cs”. And after this command, we are using the “mono” command with a filename having an extension of “.exe”. Just remember one thing, when using the “mcs” command, you must use the “.cs” extension with the filename, and with the “mono” command, you must use the “.exe” extension with the filename.
In this output, you can see it displays the length of the string which we give in the code. As the string in this code is “aeiou” and these are 5 characters so this program returns the length of the string as “5”.
Example # 2: Calculating String Length of the String that the User Entered by Using the Built-in Function
Here, we have another example in which we are getting the string from the user and then calculating the string length using the same method as described in the above example and displaying the length of the string.
We import the library of the C# program “using System”. It will access the functions and also the methods that are required in this C# code. After this, we have a namespace having the name “stringLength”. The “namespace” is used for declaring the scope that encompasses a group of items that are connected.
Now, we are going to create a class with the name “CSharp” in this C# code. We also have a “main” method in this code which is “static void Main(String [ ] args)”. It is an important part of this code. All the code is written inside the curly braces of the main method. We have “Console.WriteLine” in this “main” method which is used for printing the text on the screen. Here, we are displaying the message to the user to enter the string so that the user enters the string that he wants. For getting the input from the user, we use “Console.ReadLine”.
First, we declare and initialize a string with the name “str1” and assign “Console.ReadLine()” to this string, so that all the strings that the user enters will store in this string “str1”. After this, we use the string.Length method for finding the length of the string that the user entered. We declare and initialize an integer “length” and use “str1.Length” for calculating characters and spaces in the string. This string length is stored in this “length” of integer data type. Now, we print this length of users’ string using the “Console.WriteLine” method.
The output of the above C# code is here in the image. We use the same commands as we were using in our previous example. Let’s see in this image below how it will print the length of the string that the user enters.
We see that the user enters the string “My first program of CSharp” string length”. And it displays the length of the string as “40” as it counts the characters and also the spaces and returns the value of this string.
Example # 3: Calculating String Length Without Using the Built-in Method
Now, we are calculating the string length without using any built-in method in the C# programming in Ubuntu 20.04.
The first line of the code is “using System” which we have discussed in detail in our previous example. Then a namespace with the name “LengthOfString”. After this, the class is created with the name “Example”. You can also create the class with the name of your choice. Then, the “main” function is invoked here in this class. Inside the “main” method, we declare a string named “words”. Now, we display the message on the screen for the user to enter the string.
For displaying the message, we are using “Console.WriteLine”. By using “words = Console.ReadLine()”, all the text or string that the user enters is stored in “words” which is declared as the string data type. We declare and initialize an integer “a” in the next line. After this, we use the “foreach” loop, this loop gets the characters with the help of “char c” in “words” and then “a++” increments the value of “a” each time the character is entered by the user. Now, we have “Console.WriteLine” for printing the length of the string which we have discussed in our previous examples.
We get the output of the code which counts the characters along with spaces and displays the string length without using any built-in method.
Conclusion
In this guide, we learned about the string length in the C# program in Ubuntu 20.04. We have explained this concept in detail and demonstrated different examples for better understanding. We also show how to find the length of the string that is entered by the user. We can find the length by using the built-in function and also without using the built-in function in this guide. These examples will help you in finding the length of any string in the C# program. Also, we explained how to run C# code and get output in Ubuntu 20.04. I hope this guide will provide you with great benefits and you will easily find string length using these methods.
About the author
Aqsa Yasin
I am a self-motivated information technology professional with a passion for writing. I am a technical writer and love to write for all Linux flavors and Windows.