## Basics – What is Square Root?

Let’s say there is a number *X*, when we multiply *X with itself*, it gives *Y***.** So, *X is the square root of Y*.

E.g. 2 is the square root of 4

5 is the square root of 25.

## Square root in C++ – sqrt() function

C++ provides us an inbuilt library function to calculate the square root of any **non-negative** number.

If we pass a negative number as a parameter, then it will result in a **domain error**.

sqrt() function is defined in <cmath> header file. So, we need to include it in our program.

```
#include <cmath>
```

### Program to get Square Root in C++ using sqrt() function

```
#include <iostream>
#include <cmath>
using namespace std;
int main()
{
double squareNumber = 25.0, sqrtValue;
sqrtValue = sqrt(squareNumber);
cout << "Square root of " << squareNumber << " is " << sqrtValue << endl;
return 0;
}
```

**Output**

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## Square root function c++ in Code – Without sqrt

```
#include<stdio.h>
int mySqrt(int num) {
float temp, sqrt;
int number;
number = num;
sqrt = number / 2;
temp = 0;
// It will stop only when temp is the square of our number
while(sqrt != temp){
// setting sqrt as temp to save the value for modifications
temp = sqrt;
// main logic for square root of any number (Non Negative)
sqrt = ( number/temp + temp) / 2;
}
printf("Square root of '%d' is '%f'", number, sqrt);
return (sqrt);
}
int main() {
int number;
printf("Emter the number: \n");
scanf("%d", &number);
mySqrt(number);
}
```

### Explanation of Above Code

In the above code, we created a function, that takes the **entered number** as a parameter.

We are maintaining two more variables here, one for **storing the temporary value**. And the other one **for storing the actual square root of the number.**

`sqrt = ( number/temp + temp) / 2;`

This one line code is the core logic behind the calculation.

### Final Words

I hope you must have learned how to take the square root in c++ with two methods. If you have a better solution to the problem please comment that below or contact us via E-mail.

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