Need help with quadratic formula function

[mensch]

I can't figure out whats wrong with my program. It's supposed to calculate the quadratic formula using functions, but I think I'm messing up my function call. I get a lot of compiler errors (I'm using gnu g++)

Here's the code:

#include<iostream.h>
#include<stdlib.h>
#include<math.h>

//Prototypes
int quad(double a, double b, double c,, double &a1, double &a2);

//Main Routine
int main()
        {
        double num1, num2, num3;
        double ans1, ans2;
        int type;

        cout<<"Welcome to the .."<<endl;
        cin>>num1>>num2>>num3;
        type = quad(num1, num2, num3, ans1, ans2);

        if (type==0)
                {
                cout<<ans1<<endl;
                cout<<ans2<<endl;
                }
        }

//Functions
int quad(double a, double b, double c, double a1, &double &a2)
        {
        double temp;

        if (a==0) return -1;
        temp = b*b-4*a*c;
        if (temp<0) return -2;
        a1=(-b+sqrt(temp))/(2*a);
        a2=(-b-sqrt(temp))/(2*a);
        return 0;
        }

and here are the errors

quad.cpp:15: error: type specifier omitted for parameter
quad.cpp:15: error: `int quad(double, double, double, double&, double&)'
   redeclared as different kind of symbol
/usr/local/lib/gcc-lib/sparc-sun-solaris2.9/3.3.2/include/sys/types.h:566: error: previous
   declaration of `typedef struct quad_t quad'
/usr/local/lib/gcc-lib/sparc-sun-solaris2.9/3.3.2/include/sys/types.h:566: error: previous
   non-function declaration `typedef struct quad_t quad'
quad.cpp:15: error: conflicts with function declaration `int quad(double,
   double, double, double&, double&)'
quad.cpp: In function `int main()':
quad.cpp:26: error: no matching function for call to `_quad::_quad(double&,
   double&, double&, double&, double&)'
/usr/local/lib/gcc-lib/sparc-sun-solaris2.9/3.3.2/include/sys/types.h:565: error: candidates
   are: _quad::_quad()
/usr/local/lib/gcc-lib/sparc-sun-solaris2.9/3.3.2/include/sys/types.h:565: error:
                  _quad::_quad(const _quad&)
quad.cpp: At global scope:
quad.cpp:37: error: parse error before `double'
quad.cpp: In function `int quad(...)':
quad.cpp:38: error: `int quad(...)' redeclared as different kind of symbol
/usr/local/lib/gcc-lib/sparc-sun-solaris2.9/3.3.2/include/sys/types.h:566: error: previous
   declaration of `typedef struct quad_t quad'
/usr/local/lib/gcc-lib/sparc-sun-solaris2.9/3.3.2/include/sys/types.h:566: error: previous
   non-function declaration `typedef struct quad_t quad'
quad.cpp:38: error: conflicts with function declaration `int quad(...)'
quad.cpp:41: error: `a' undeclared (first use this function)
quad.cpp:41: error: (Each undeclared identifier is reported only once for each
   function it appears in.)
quad.cpp:42: error: `b' undeclared (first use this function)
quad.cpp:42: error: `c' undeclared (first use this function)
quad.cpp:44: error: `a1' undeclared (first use this function)
quad.cpp:45: error: `a2' undeclared (first use this function)

Thanks!

[a_c]

//Functions
int quad(double a, double b, double c, double a1, &double &a2)

you have misplaced an "&".

[mensch]

ah thanks. That actually wasnt the main problem, but i figured it out. I just had to rename my quad function. It was predefined.