Nov 22, 2013 at 2:23pm UTC
Please help. I'm student and now working on the program that can solve quadratic equations. The text that appears on screen and solutions should depend from discriminant, but it doesn't.
Also, if discriminant less than zero, it doesn't show that there are no solutions. Instead it shows "-2147387..."
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#include <iostream>
#include <math.h>
using namespace std;
int main ()
{
int a, b, c, x, D, result1, result2, result3;
cout << "Enter coefficient of x^2: " << endl;
cin >> a;
cout << "Enter coefficient of x: " << endl;
cin >> b;
cout << "Enter the third component: " << endl;
cin >> c;
D = ( b * b ) - ( 4 * a *c );
if (D > 0)
cout << "This equation has 2 solutions." << endl;
result1 = ( 0 - b + sqrt (D) ) / (2 * a);
cout << "The first solution is: " << result1 << endl;
result2 = ( 0 - b - sqrt (D) ) / (2 * a);
cout << "The second solution is: " << result2 << endl;
if (D = 0)
cout << "This equation has only solution." << endl;
result3 = ( 0 - b ) / (2 * a);
cout << "The solution is: " << result3 << endl;
if (D < 0)
cout << "This equation has no solutions." << endl;
}
Last edited on Nov 22, 2013 at 2:24pm UTC
Nov 22, 2013 at 2:43pm UTC
The variables should be of type double
instead of int
.
if (D = 0)
here the =
is the assignment operator, it should instead be ==
to test for equality.
The header should be #include <cmath>
rather than <math.h>
Nov 22, 2013 at 2:48pm UTC
Thanks, now it works better, but in all three situations after the correct text it shows "This equation has no solutions".
Here's edited code:
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#include <iostream>
#include <math.h>
using namespace std;
int main ()
{
int a, b, c, x, D, result1, result2, result3;
cout << "Enter coefficient of x^2: " << endl;
cin >> a;
cout << "Enter coefficient of x: " << endl;
cin >> b;
cout << "Enter the third component: " << endl;
cin >> c;
D = ( b * b ) - ( 4 * a *c );
if (D > 0)
{
cout << "This equation has 2 solutions." << endl;
result1 = ( 0 - b + sqrt (D) ) / (2 * a);
cout << "The first solution is: " << result1 << endl;
result2 = ( 0 - b - sqrt (D) ) / (2 * a);
cout << "The second solution is: " << result2 << endl;
}
else if (D == 0)
{
cout << "This equation has only solution." << endl;
result3 = ( 0 - b ) / (2 * a);
cout << "The solution is: " << result3 << endl;
}
else ;
{
cout << "This equation has no solutions." << endl;
}
}
Last edited on Nov 22, 2013 at 2:50pm UTC
Nov 22, 2013 at 2:51pm UTC
else (D < 0);
You have a stray terminator (;).
Nov 22, 2013 at 2:53pm UTC
Line 30 else ;
remove the semicolon
Line 8, change int
to double
Line 2, change <math.h>
to <cmath>
Last edited on Nov 22, 2013 at 2:55pm UTC
Nov 22, 2013 at 2:54pm UTC
Oh, thanks a lot! Now it's working fine. :)