In this article, we will study different ways we can find the square root of a number in C/C++.

## Program of Square root using the standard library

The simplest way to find square root of a number is to use the standard library function *sqrt()*.

double sqrt(double arg);

It accepts a single argument of type double and returns the square root of that number. *The sqrt() is defined in math.h library*.

Example,

```
#include<stdio.h>
#include<math.h>
int main() {
int n;
double v;
printf("Enter a Number: ");
scanf("%d",&n);
v = sqrt(n);
printf("Square Root of %d is %f",n,v);
}
```

**Output**

```
Enter a Number: 13
Square Root of 13 is 3.605551
```

## Program of Square root using Binary Search Algorithm

We can use binary search to find approximate value of square root of a number.

### Steps

- Let N be the number whose square root we need to calculate.
- Initialize start = 0 and end = N.
- Repeat the following steps while (end – start) > 0.00001 (it defines the precision)
- Set mid = (start+end)/2.
- If mid*mid < N, then set start = mid.
- If mid*mid >= N, then set end = mid.

- The final answer is stored in mid.

```
#include<stdio.h>
#include<math.h>
int main() {
int n;
double start,end,mid;
printf("Enter a Number: ");
scanf("%d",&n);
start = 0, end = n;
while((end - start)>=0.000001){
mid = (start + end)/2;
if(mid*mid < n)
start = mid;
if(mid*mid >= n)
end = mid;
}
printf("Square Root of %d is %f",n,mid);
}
```

**Output**

```
Enter a Number: 13
Square Root of 13 is 3.605551
```

**Read**

Check if a number is Prime

Left-Shift Array by One

Reverse a String without strrev()