# sqrt() function with example in C++

C++ sqrt() function: Here, we are going to learn about the sqrt() function with example of cmath header in C++ programming language?
Submitted by IncludeHelp, on April 26, 2019

## C++ sqrt() function

sqrt() function is a library function of cmath header (<math.h> in earlier versions), it is used to find the square root of a given number, it accepts a number and returns the square root.

Note: If we provide a negative value, sqrt() function returns a domain error. (-nan).

Syntax of sqrt() function:

```    sqrt(x);
```

Parameter(s): x – a number whose square root to be calculated.

Return value: double – it returns double value that is the square root of the given number x.

Example:

```    Input:
int x = 2;

Function call:
sqrt(x);

Output:
1.41421
```

### C++ code to demonstrate the example of sqrt() function

```// C++ code to demonstrate the example of
// sqrt() function

#include <iostream>
#include <cmath>
using namespace std;

// main code section
int main()
{
float x;

//input the value
cout<<"Enter a number: ";
cin>>x;

// calculate the square root
float result = sqrt(x);
cout<<"square root of "<<x<<" is = "<<result;
cout<<endl;

return 0;
}
```

Output

```First run:
Enter a number: 4
square root of 4 is = 2

Second run:
Enter a number: 10.234
square root of 10.234 is = 3.19906

Third run:
Enter a number: 0
square root of 0 is = 0

Fourth run:
Enter a number: -10
square root of -10 is = -nan
```