/* --*-- SOLVE A QUADRATIC EQUATION --*-- written by: BlackHammer Program to find both roots of a 2nd degree equation 0 = a*x*x + b*x + c The program gets three numbers from the user a,b and c. program calculates and displays to the user: 1. roots result: two roots, one root, infinite roots or no roots. 2. the value of the one or two roots if found. */ #include #include using namespace std; enum sols_t { TW_RT, ON_RT, NO_RT, IN_RT }; void read_data(double &, double &, double &); enum sols_t solve_linear(double, double, double &); enum sols_t solve_quadratic(double, double, double, double &, double &); void print_data(double, double, enum sols_t); double find_disc(double, double, double); int main() { double a, b, c, x1 = 0 , x2 = 0; enum sols_t num_of_sols; read_data(a, b, c); if (a == 0) num_of_sols = solve_linear(b, c, x1); else num_of_sols = solve_quadratic(a, b, c, x1, x2); print_data(x1, x2, num_of_sols); cout << endl << endl << endl << endl; return 0; } void read_data(double &a, double &b, double &c) { cout << "\n\n Equation: a*X*X + b*X + c = 0"; cout << "\n\n Enter 3 values for a b c: "; cin >> a >> b >> c; } enum sols_t solve_linear(double a, double b, double &x1) { if (b == 0) return IN_RT; if (a == 0) return NO_RT; x1 = (-b) / a; return ON_RT; } enum sols_t solve_quadratic(double a, double b, double c, double &x1, double &x2) { double disc; disc = find_disc(a, b, c); if (disc < 0) return NO_RT; x1 = (-b + disc) / (2 * a); if (disc == 0) return ON_RT; x2 = (-b - disc) / (2 * a); return TW_RT; } double find_disc(double a, double b, double c) { double result = b*b - 4 * a *c; if (result < 0) return result; return sqrt(result); } void print_data(double root1, double root2, enum sols_t num_of_sols) { if (num_of_sols == NO_RT) cout << "\n\n No real roots"; else if (num_of_sols == IN_RT) cout << "\n\n Every X solves"; else if (num_of_sols == ON_RT) cout << "\n\n Solution: " << root1; else cout << "\n\n Solution: " << root1<<" "<