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 =         

 

Root 2=        

 

 

 

 

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;
}

Sample Output

Root 1 := 6

Root 2 := -2

Process returned 0 (0x0) execution time : 2.083 s

Press any key to continue.  

Enhancements

We can further enhance the program to prompt the input values of a, b, c to the user. Right now we have to modify the code for the values.

 

Generate the equation string based on the values of a, b, and c and display the equation string in the output.

Take into consideration the imaginary roots if the discriminant is less than 0. The logic is outlined in the flowchart link

Flowchart :

https://www.testingdocs.com/questions/raptor-flowchart-to-find-quadratic-equation-roots/  

 

The IDE used in the tutorial is Code:: Blocks. To download and install Code Blocks follow the link:

https://www.testingdocs.com/download-and-install-codeblocks/

For more information on Code Blocks IDE used in the program, visit the official website of Code blocks IDE:

http://www.codeblocks.org/