I'm having problems with putting formulas in my code.

[tall antelope]

Hi, I'm a beginning programmer! I'm learning out of a book, and the part I'm reading right now is all about inputs and outputs. I decided that I wanted to practice what I'd learned so far, so I tried to write a program that did the quadratic formula for me.

I'm fairly certain that my formula is correct, but whenever I put numbers in, the wrong answers come out. I put 1, 6, and 9 in for their respective a, b, and c values. This means that the two x's should be equal to -3. However, it tells me that the values are equal to -19 and 13. What have I done wrong?

 #include <iostream>

using namespace std;

int main()
{	// I declare my a, b, and c as integers*\
	because I wanted it to be pretty simple,*\
	but I declared the x's as float so they can have decimals.

	int a, b, c;
	float x1, x2;

	//Input of the "a" value
	cout <<"What does 'a' equal? ";
	cin >> a;
	//Input of the "b" value
	cout << "What does 'b' equal? ";
	cin >> b;
	//Input of the "c" value
	cout << "What does 'c' equal? ";
	cin >> c;

	//Quadratic Formula
	x1= (-b + ((b^2)-(4*a*c))^(1/2))/(2*a);

	x2= (-b - ((b^2)-(4*a*c))^(1/2))/(2*a);

	//Numbers are put into the equation and the values of the two x's are given.
	cout << "x1 is equal to " << x1 <<endl;
	cout << "x2 is equal to " << x2 << endl;

system("pause");
return 0;
}

[Chervil]

The ^ operator isn't used for powers, it is actually the bitwise exclusive or XOR.

For b² use simplyb*b
(there is also the pow() function to raise a number to other powers)
For square root, use the sqrt() function
#include <cmath> header for those functions.

Some of your variables are of type int. I'd recommend that you use a floating-point type for all the variables in this case. Type double would be usual, float would work but it's less precise and I'd not recommend it for everyday use.

[The illusionist mirage]

Where are you calculating x1 and x2? These statements have no use:

x1= (-b + ((b^2)-(4*a*c))^(1/2))/(2*a);
	x2= (-b - ((b^2)-(4*a*c))^(1/2))/(2*a);

Show the actual statements in your program.

[coder777]

Looke here:

http://www.cplusplus.com/doc/tutorial/operators/

to learn what the operators do.

^ is not power. You need to use the function pow() instead:

http://www.cplusplus.com/reference/cmath/pow/?kw=pow

(1/2) will result in 0 since it's an integer operation. Use at least one none integer value like (1.0/2)

[tall antelope]

Okay, I fixed it! Thank you for the help!

I wasn't aware of the new header that I needed to use (I guess I jumped ahead a bit of where I thought I was)