---
title: "What are differences between system.stringbuilder and system.string?"  
description: "What are differences between system.stringbuilder and system.string?"  
author: "Sumit Kesarwani"  
published: 2014-11-20  
updated: 2020-09-21  
canonical: https://www.mindstick.com/interview/2248/what-are-differences-between-system-stringbuilder-and-system-string  
category: ".net"  
tags: ["c#", ".net", "string"]  
reading_time: 1 minute  

---

# What are differences between system.stringbuilder and system.string?

The main difference is system.string is immutable and system.stringbuilder is a mutable. Append keyword is used in string builder but not in system.string.

Immutable means once we created we cannot modified. Suppose if we want give new value to old value simply it will discarded the old value and it will create new instance in memory to hold the new value.

## Answers

### Answer by Sumit Kesarwani

The main difference is system.string is immutable and system.stringbuilder is a mutable. Append keyword is used in string builder but not in system.string.

Immutable means once we created we cannot modified. Suppose if we want give new value to old value simply it will discarded the old value and it will create new instance in memory to hold the new value.


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Original Source: https://www.mindstick.com/interview/2248/what-are-differences-between-system-stringbuilder-and-system-string

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