#### find the square root of a number

Given a number we have to **find the square root of a number** and print the resultant value .

So what is **square root** of number?

Square root of a number is calculated by mathematically

squareroot(num)=n*n

to solve this problem we have inbuilt library in c++ sqrt() which will make easier to calculate during any test.

**Example:**

**input**:36
**output**:6
**input**:25
**output**:5

**Approach 1:Using sqrt function**

**Code-**

#include<bits/stdc++.h> using namespace std; int main() { int num; cout<<"Enter a number "<<endl; cin>>num; double root=sqrt(num);//this is stl library function. cout<<root<<endl; }

**Approach 2:Without sqrt function**

**Logic:**

`this method is same like binary search, we will check square root of number between low and high value.`

#include<bits/stdc++.h> using namespace std; int main() { cout<<"Enter a number"<<endl; int num; cin>>num; int square; if(num==0||num==1) { square=num; } else { //lets apply binary search concept here. int mid=0; int low=1; int high=num; while (low <= high) { int mid = (low + high) / 2; if (mid*mid == num) { return mid; } if (mid*mid < num) { low = mid + 1; square = mid; } else { high = mid-1; } } } cout<<square<<endl; return 0; }

**Output:**

enter a number:16 4

**Time complexity**:0(logN)

**Space Complexity**:O(1)