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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