#include #include using namespace std; const int X1_INDEX= 1; const int X2_INDEX= 0; const int A_INDEX = 0; const int B_INDEX = 1; const int ROOTS = 2; const int C_INDEX = 3; const int COEFFS = 3; void GetCoefficients(double& a, double& b, double& c); // Get the coefficients for the Quadratic equation. // @param a, b, c reads the coefficients static bool SolveQuadratic(double a, double b, double c,double *px1, double *px2); // Solve the quadratic equation represented by a, b, c as coefficients // @param a, b, c are the coefficients // @param px1, px2 are the pointers to the roots // @return true if the roots are real or false when imaginary. static void DisplayRoots(double x1, double x2, bool isReal); // Display the roots using isReal to determine how to print. int main() { char retry; do { // Using arrays to store coeffs and solutions. double coeffs[COEFFS], solutions[ROOTS]; double *px1 = &solutions[X1_INDEX]; // Use pointers in SolveQuadratic double *px2 = &solutions[X2_INDEX]; bool isReal = true; // Read the coefficients GetCoefficients(coeffs[A_INDEX], coeffs[B_INDEX], coeffs[C_INDEX]); // Solve the equation isReal = SolveQuadratic(coeffs[A_INDEX], coeffs[B_INDEX], coeffs[C_INDEX], px1, px2); // Print the results. DisplayRoots(solutions[X1_INDEX], solutions[X2_INDEX], isReal); cout << "Try again (y or Y): "; cin >> retry; } while (retry == 'Y' || retry == 'y'); return 0; } // GetCoefficient reads the coefficients // @param a, b, c reads the coefficients void GetCoefficients(double& a, double& b, double& c) { cout << "Enter coefficients a, b and c: "; cin >> a >> b >> c; } // SolveQuadratic solves the quadratic equation and returns the roots // @param a, b, c are the coefficients // @param px1, px2 are the pointers to the roots // @return true if the roots are real or false when imaginary. bool SolveQuadratic(double a, double b, double c, double* px1, double* px2) { double discriminant = b * b - 4 * a*c; // Two different roots for this equation if (discriminant > 0) { *px1 = (-b + sqrt(discriminant)) / (2 * a); *px2 = (-b - sqrt(discriminant)) / (2 * a); return true; } // One root satisfies both else if (discriminant == 0) { *(px1) = (-b + sqrt(discriminant)) / (2 * a); *px2 = *px1; return true; } // Read part in px1, imaginary part in px2. else { *px1 = -b / (2 * a); *px2 = sqrt(-discriminant) / (2 * a); return false; } } // // DisplayRoots - display 2 roots using information of real and imaginary. // @param x1 - always contains a root. // @param x2 - only contains a root when different or isReal false. // @param isReal - tells whether roots are real or imaginary. static void DisplayRoots(double x1, double x2, bool isReal) { if (isReal) { if (x1 != x2) { cout << "Roots are real and different." << endl; cout << "x1 = " << x1 << endl; cout << "x2 = " << x2 << endl; } else if (x1 == x2) { cout << "Roots are real and same." << endl; cout << "x1 = x2 =" << x1 << endl; } } else { cout << "Roots are complex and different." << endl; cout << "x1 = " << x1 << "+" << x2 << "i" << endl; cout << "x2 = " << x1 << "-" << x2 << "i" << endl; } }
There is an error in this code, and its making it stop completing the program properly after the do-while loop in main. My problem is that for some reason coeffs[C_INDEX] isn't reading in properly, and it just gives some random output, but a and b work fine. How can I fix this?
#include <iostream>
#include <cmath>
using namespace std;
const int X1_INDEX= 1;
const int X2_INDEX= 0;
const int A_INDEX = 0;
const int B_INDEX = 1;
const int ROOTS = 2;
const int C_INDEX = 3;
const int COEFFS = 3;
void GetCoefficients(double& a, double& b, double& c);
// Get the coefficients for the Quadratic equation.
// @param a, b, c reads the coefficients
static bool SolveQuadratic(double a, double b, double c,double *px1, double *px2);
// Solve the quadratic equation represented by a, b, c as coefficients
// @param a, b, c are the coefficients
// @param px1, px2 are the pointers to the roots
// @return true if the roots are real or false when imaginary.
static void DisplayRoots(double x1, double x2, bool isReal);
// Display the roots using isReal to determine how to print.
int main() {
char retry;
do {
// Using arrays to store coeffs and solutions.
double coeffs[COEFFS], solutions[ROOTS];
double *px1 = &solutions[X1_INDEX]; // Use pointers in SolveQuadratic
double *px2 = &solutions[X2_INDEX];
bool isReal = true;
// Read the coefficients
GetCoefficients(coeffs[A_INDEX], coeffs[B_INDEX], coeffs[C_INDEX]);
// Solve the equation
isReal = SolveQuadratic(coeffs[A_INDEX], coeffs[B_INDEX], coeffs[C_INDEX],
px1, px2);
// Print the results.
DisplayRoots(solutions[X1_INDEX], solutions[X2_INDEX], isReal);
cout << "Try again (y or Y): ";
cin >> retry;
} while (retry == 'Y' || retry == 'y');
return 0;
}
// GetCoefficient reads the coefficients
// @param a, b, c reads the coefficients
void GetCoefficients(double& a, double& b, double& c)
{
cout << "Enter coefficients a, b and c: ";
cin >> a >> b >> c;
}
// SolveQuadratic solves the quadratic equation and returns the roots
// @param a, b, c are the coefficients
// @param px1, px2 are the pointers to the roots
// @return true if the roots are real or false when imaginary.
bool SolveQuadratic(double a, double b, double c, double* px1, double* px2)
{
double discriminant = b * b - 4 * a*c;
// Two different roots for this equation
if (discriminant > 0) {
*px1 = (-b + sqrt(discriminant)) / (2 * a);
*px2 = (-b - sqrt(discriminant)) / (2 * a);
return true;
}
// One root satisfies both
else if (discriminant == 0) {
*(px1) = (-b + sqrt(discriminant)) / (2 * a);
*px2 = *px1;
return true;
}
// Read part in px1, imaginary part in px2.
else {
*px1 = -b / (2 * a);
*px2 = sqrt(-discriminant) / (2 * a);
return false;
}
}
//
// DisplayRoots - display 2 roots using information of real and imaginary.
// @param x1 - always contains a root.
// @param x2 - only contains a root when different or isReal false.
// @param isReal - tells whether roots are real or imaginary.
static void DisplayRoots(double x1, double x2, bool isReal)
{
if (isReal) {
if (x1 != x2) {
cout << "Roots are real and different." << endl;
cout << "x1 = " << x1 << endl;
cout << "x2 = " << x2 << endl;
}
else if (x1 == x2) {
cout << "Roots are real and same." << endl;
cout << "x1 = x2 =" << x1 << endl;
}
}
else {
cout << "Roots are complex and different." << endl;
cout << "x1 = " << x1 << "+" << x2 << "i" << endl;
cout << "x2 = " << x1 << "-" << x2 << "i" << endl;
}
}
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