Displaying wrong result . Why?

Question

#include <iostream>
#include <cmath>
using namespace std;

int main() {
int a,b,c;
cin >>a;
cin >>b; // values //
cin >>c;
int d = sqrt((b*b)-(4*a*c)); // discriminant //
int alpha = -b+d/2*a; //formula //
int beeta = -b-d/2*a;
cout <<"D="<<d<<endl;
cout <<"alpha="<<alpha<<endl;
cout <<"beeta="<<beeta<<endl;
return 0;
}

Answer 1

Becz you have written int alpha = -b+d/2a and same for beta
Here you need to put round bracket u dividing value of d only
It should be like this
(-b +d)/2a
...

Answer 2

Not too sure, but you might need to check whether the use of `float` or `double` as type for <a>, <b> and <c> helps. I'm just guessing it was due to integer division issue.

(Edit)
Might be considerable to rather define all variables involved in the calculation as floating point type.

Answer 3

It is only working for few equations.

Answer 4

These lines are incorrect:

int alpha = -b+d/2*a; /7/formula //
int beeta = -b-d/2*a;

It is an error in order of operations. Understand that -b+d/2*a is interpreted as -b+(d/2)*a.

Change them to:

int alpha = (-b+d)/(2*a); /7/formula //
int beeta = (-b-d)/(2*a);

And as already pointed out, it is likely a better choice to use floats instead of ints if accuracy is important.