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sqrtl function in C++

Mathematical operations are vital elements in any field of programming which may be used to solve various types of problems. With respect to C++ and square roots, one of the most prominent functions is sqrtl. In this blog post, we will discuss the syntax, code samples, and Output of qrootl, which plays a crucial role in numerical calculations.

The 'sqrtl' function belongs to the C++ Standard Library, and it can be found in the '<cmath>'. This square root calculator is intended to find the square root of some long double number. Long double makes sure that the function can manage more extended and finer floating-point numbers than float and double.


It is simple for everyone to understand the syntax of the sqrtl function. This function only requires one argument in type long double, and it also gives out the square root of that value in long double. Here is the basic syntax:

x: It is the number for which the square root must be found.


Let's take an example to understand the sqrtl function in C++a.


Enter a number: 144
Square root of 144 is: 12


Header Inclusions:

The code includes two standard C++ headers: <iostream> and <cmath>. I/O operations are performed using <iostream>. Among the functions provided by the <cmath> is sqrtl which gives the square root with long double precision.

Main Function:

The starting point for its execution is at the main function. It happens to be the main entry of any C++ program.

Variable Declaration:

An extended double variable named number is set with a value of 25.0. Long double is a data type used in computer science, which offers more precision than float and double.

Square Root Calculation:

Sqrtl() function is used to find the magnitude that exists between the number and zero.
It stores the result in a new long double variable called result.


The result is displayed by using a std::cout statement. Additionally, the original number and the square root result are displayed.

Return Statement:

A successful program run is signified through a return 0; statement. It returns the value zero to the operating system, meaning that the system stopped running without any errors.

Advantages of the Sqrtl() Function:

There are several advantages of the sqrtl() in C++. Some main advantages of the sqrtl() are as follows:

Precision with Long Double:

Sqrtl works with long double types of numbers that have high accuracy in comparison with float and double values. Therefore, this precision is indispensable for such representations that require precise presentation of floating-point numbers.

Standard Library Reliability:

sqrtl is a member of the C++ standard library (<cmath>), which means you are guaranteed of its availability irrespective of your C++ implementation. It conforms to language definitions as an orthodox function, making code portable.

Ease of Use:

The sqrtl function is very straightforward. However, the convenience comes at a cost that abstracts the complexities of implementing a square root algorithm.

Disadvantages of the Sqrtl() Function:

There are several disadvantages of the sqrtl() in C++. Some main disadvantages of the sqrtl() are as follows:

Limited to Floating-Point Numbers:

sqrtl function has been specified explicitly for floating point numbers, whose applications are restricted to taking square roots by purely real numbers. For an integer-based square root, it might not work or be suitable.

Potential for Precision Loss:

However, the use of a long double can provide more precise results. Nevertheless, it may still fail to meet some cases where arbitrary precision is needed. Alternative libraries or algorithms may also be required for precision issues in critical applications.

Performance Considerations:

The sqrtl function may be computationally expensive for extreme data sizes or time-critical applications, as calculating square root can generally be a costly operation. Alternative algorithms and/or optimizations should be considered in performance-critical settings.


In conclusion, it is important to mention that the sqrtl function in C++ works on the types of long double, providing accuracy, reliability, and convenience. It makes it suitable for different applications that involve precise numerical calculations. However, it is specific to floating point numbers that can lead to preciseness loss in important cases. It has performance issues when dealing with big data sets and depends on the library implementation. These should guide developers as they decide on whether to use sqrtl that is consistent with the needs of the project and consider other options in case it gives a less accurate value.

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