C++ Programming Code Examples
C++ > Algorithms Code Examples
Quadratic Equation
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/* Quadratic Equation */
#include <math.h>
#include <iostream>
using namespace std;
struct graphPoint{
double x, y;
};
class QuadraticEquation{
public:
QuadraticEquation(double A = 0.0, double B = 0.0, double C = 0.0) : a(A), b(B), c(C){
xintercepts[0].x = 0.0;
xintercepts[0].y = 0.0;
xintercepts[1].x = 0.0;
xintercepts[1].y = 0.0;
}
~QuadraticEquation(){}
int getxintercepts(){
double temp = (b * b) - (4 * a * c);
if(temp < 0){
cout << "##-Square Root Error:\n"
<< " ##- SquareRoot ( " << temp << " )\n";
return 1;
}
temp = sqrt ( temp );
xintercepts[0].x = (b * -1) - temp;
xintercepts[0].x = xintercepts[0].x / (2 * a);
xintercepts[1].x = (b * -1) + temp;
xintercepts[1].x = xintercepts[1].x / (2 * a);
return 0;
}
void displayequation(){
if(a != 0){
cout << a;
cout << "x^2";}
if(b >= 1 & a != 0)
cout << "+";
if(b != 0)
cout << b << "x";
if(c > 0)
cout << "+";
if(c != 0)
cout << c;
if(a == 0 & b == 0 & c == 0)
cout << 0;
cout << "=0" << endl;
}
double a, b, c;
graphPoint xintercepts[2];
};
void creditsHelp();
void wierdGetch();
int main(int argc, char *argv[]){
cout << "@-Quadratic Equation Solver\n"
<< " @-Karlan Mitchell karlanmitchell-at-comcast-dot-net\n"
<< " @-For Credits/Help enter 0 for A\n";
double a,b,c;
cout << "Enter in values for equation\n";
for(;;){
cout << "A: ";
cin >> a;
if(a == 0.0){
creditsHelp();
continue;
}
break;
}
cout << "B: ";
cin >> b;
cout << "C: ";
cin >> c;
QuadraticEquation test(a,b,c);//create the class
test.displayequation();//display the equation with the class function
switch(test.getxintercepts()){/* I am using a switch here instead of
* an if because I constanly add/remove
* error messages to this function*/
case 1:
cout << "!!-Equation not possible\n"
<< " !!-If you know that it is possible, please contact me about a bug\n";
exit(1);
break;
}
cout << "x = " << test.xintercepts[0].x << " | " << test.xintercepts[1].x << endl;
cout << "(" << test.xintercepts[0].x << ", 0) & (" << test.xintercepts[1].x << ", 0)\n";
wierdGetch();
return 0;
}
void creditsHelp(){
cout << "\nThis program was created by me to make my math homework easier\n\n"
<< "What it does:\n"
<< "It takes in the 'a', 'b', and 'c' values for a quadratic equation\n"
<< "which equals zero.\n"
<< "EX: \"x^2 - 3x + 2 = 0\" is equal to \"(x - 2)(x - 1) = 0\"\n"
<< " ax^2 + bx + c = 0\n"
<< " The 'a','b', and 'c' values for the equation would be 1, -3, and 2\n"
<< " The x intercepts for this would be (2, 0) and (1, 0)\n"
<< " 2^2 - 3(2) + 2 = 0 and 1^2 - 3(1) + 2 = 0\n\n"
<< "Why would I use this:\n"
<< "1) You are in Algebra I/II or Geometry\n"
<< "2) Your too lazy to do the quadratic equation on your own which is:\n"
<< " x=( -b +/- sqrt(bb - 4ac) ) / (2a)\n";
wierdGetch();
exit(0);
}
void wierdGetch(){
cout << "Press enter to exit...";
getchar();getchar();//Why do I need, two? The world may never know
}
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