How to declare sqrt ? As code is not running and telling error in sqrt

Question

#include <iostream>
using namespace std;

int main() {

int a , b , c , discriminant , x1 , x2 , real_part , imaginary_part ;
cout << "Enter coefficients of a , b , c " << endl ;
cin >> a >> b >> c ;
discriminant = (b*b) - (4*a*c) ;
if (discriminant>0) {
cout << "Roots are real and different" ;
x1 = (-b + sqrt(discriminant)) / (2*a) ;
x2 = (-b - sqrt(discriminant )) /(2*a) ;
cout << "x1 = " << x1 << "x2 = " << x2 ;
}
else if (discriminant == 0) {
cout << "Roots are equal\n" ;
x1 = (-b/2*a) ;
cout << "x1=x2 = " << x1 ;
}
else {
real_part = (-b/2*a) ;
imaginary_part = sqrt (-discriminant) /2*a ;
cout << "x1 is " << real_part <<"+" << imaginary_part << "i" ;
}
return 0;
}

Answer 1

Include the math library:

#include <cmath>

Answer 2

Thanks Brian Sir

Answer 3

Keshav Karn you're welcome!