quadeq.cpp

求解二次方程的小程序

#include <iostream.h>
#include <math.h> 
using namespace std;
int main()
{
cout << "\n\tAX^2+BX+C=0\n";
cout << "\t Quadratic equation\n"; // < i think it's called
/* AX^2+BX+C=0
       
    x= (-b +- sqrt(b^2-4ac))/2a        sqrt=square root     
*/



float a,b,c,d,x;
cout << "A:";
cin >> a;
cout << "\nB:";
cin >> b;
cout << "\nC:";
cin >> c;

d=b*b-(4*a*c);

if(d<0)
{
cout << "\nNo solution";
}
else
{
x= (-b)/(2*a);
}

if(d==0)
{
cout << "\nX="<<x;
}

if(d>0)
{
x=(-b+ sqrt(d) )/(2*a); //    sqrt=square root
cout << "\nX1 = "<< x;
x=(-b- sqrt(d) )/(2*a);
cout << "\nX2 = "<< x;



}
}