# Quadratic Equation (getting input and doing calculations)

*Part of* TutorialFundamentals

## Description

This program will calculate the real roots for a user-specified quadratic equation.

## Example

import std.c.stdio; /* for scanf */ import std.stdio; /* for writef/writefln */ import std.math; /* for sqrt */ int main() { double a, b, c, d; writefln("For the equation: ax^2 + bx + c = 0"); writef("What is a? "); scanf("%lf", & a); writef("What is b? "); scanf("%lf", & b); writef("What is c? "); scanf("%lf", & c); writefln("\nFor a = %s, b = %s, c = %s:", a, b, c); d = (b*b) - (4*a*c); if (d < 0) { writefln("There are no real roots."); } else { double r1, r2; r1 = (-b - sqrt ( d )) / (2*a); r2 = (-b + sqrt ( d )) / (2*a); if(r1 == r2) writefln("Root: %s", r1); else writefln("Roots: %s, %s", r1, r2); } return 0; } /* For the quadratic equation: ax^2 + bx + c = 0 Roots = (-b +/- sqrt ( b^2 - 4ac )) / 2a For example: a = 1, b = -5, c = 6 The roots are 2 and 3. */

## More Information

Note the use of curly braces around the bodies of the *if* and *else* clauses. These are *compound statements* and allow multiple statements to be executed as part of conditional and looping statements, such as *if-else* and *while*.