Table of Contents

Overview

In this tutorial, we will write a simple C++ Program to Find Quadratic Equation Roots. The roots for the equation can be calculated as shown below:

Root 1 = $\huge \frac{-b + \sqrt{b^{2} - 4*a*c}}{2*a}$

Root 2= $\huge \frac{-b - \sqrt{b^{2} - 4*a*c}}{2*a}$

Quadratic Roots C++ Program

C++ Program

#include 
#include 
using namespace std;

// ########################################################
//
// -b + SQRT( b^2 - 4ac)
// Root 1 = -------------------------------
// 2a
//
// -b - SQRT( b^2 - 4ac)
// Root 2 = -------------------------------
// 2a
//
//
// www.TestingDocs.com
//##########################################################

int main()
{
 float a = 3.0, b = -12.0, c = -36.0;
 // Equation is 3x^2 -12x - 36 = 0
 float sqRootPart = sqrt( b*b - 4*a*c );
 //Find the roots
 float eqRoot1 = (-b + sqRootPart)/(2*a);
 float eqRoot2 = (-b - sqRootPart)/(2*a);
 //Output
 cout << "Root 1 := " << eqRoot1 << endl;
 cout << "Root 2 := " << eqRoot2 << endl;

 return 0;
}

C++ Program Root Finding