This little program I wrote for class, written in C++

it takes 3 inputs for a, b, and c and gives you the roots of the quadratic equation, pretty simple stuff.

here you go … any feedback will be appreciated. [code language=”cpp” wraplines=”true” smarttabs=”true” tabsize=”4″]
#include <iostream> // used for input & output
#include <cstdlib> // standard library
#include <cmath> // used for sqrt()
#include <iomanip> // used for setprecision …
using namespace std;

int main(){
// Variables used in quadratic equation a,b,c For answer x1 and x2
double a,b,c,x1,x2,discr; //discriminant is what under the square root in the formula
// input assignment for the constant values of a,b,c
cout<<"Enter Value for a: "; // User input for a
cin>>a;
cout<<"Enter Value for b: "; // User input for b
cin>>b;
cout<<"Enter Value for c: "; // User input for c
cin>>c;

// Calculations && OUTPUT
discr = (pow(b, 2) – 4 * a * c); //discriminant used to check whether the roots will be real or complex
cout << fixed << setprecision(2)<<endl; // setting the decimal value to 2
if (a == 0.0) // checks if a = 0, if true output message then close application.
{
cout << "If a=0, then the equation is not quadratic." << endl << endl;
return 0;
}

if (discr>0.0) // if discriminant is greater than zero then it has 2 real roots
{
cout << "For a= " << a << ", b= " << b << ", c= " << c << endl;
//x1
x1 = (-b + sqrt(b*b – 4 * a*c)) / (2 * a); //using quadratic equation with + sign then assign the value to x1
//x2
x2 = (-b – sqrt(b*b – 4 * a*c)) / (2 * a); //using quadratic equation with – sign then assign the value to x2
cout << "The roots of the quadratic equation are " << x1 << " and " << x2 << endl << endl;
}

else if (discr==0.0) // if discriminant equal zero then it has one real root
{
cout << "For a= " << a << ", b= " << b << ", c= " << c << endl;
x1 = (-b) / (2 * a);
cout << "The root of the quadratic equation is " << x1 << endl << endl;
}

else if (discr < 0.0) // if discriminant less than zero then it has two complex roots
{
cout << "For a= " << a << ", b= " << b << ", c= " << c << endl;
cout << "The roots of the quadratic equation are " << (-b / 2 * a) << "+" << sqrt(-discr) / (2 * a)<<"i and "<<(-b/(2*a))<<"-"<<sqrt(-discr)/(2*a)<<"i\n\n";
}

return 0;
}

[/code]

if you have any question leave it in the comment 🙂

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