是求一元二次方程的实数根

以下程序的功能是求一元二次方程的实数根。

#include “stdio.h”

#include “math.h”

double *quadratic(double *factor)

{   static double result[2];

    double delta;

    delta=factor[1]*factor[1]-4*factor[0]*factor[2];

    if(delta<0) return 0;

    delta=sqrt(delta);

    result[0]=(-factor[1]+delta)/(2*factor[0]);

    result[1]=(-factor[1]-delta)/(2*factor[0]);

    return result;

}

void main()

{   double fun[3],r; ★

    printf(“Please enter three factors:”);

    scanf(“%f%f%f”,&fun[0],&fun[1],&fun[2]); ★

    r=quadratic(fun[3]); ★

    if(r)

        printf(“The solution is: X1=%lf\tX2=%lf\n”,r[0],r[1]);

    else

       printf(“No solution!\n”);

}

#include “stdio.h”
#include “conio.h”
#include “math.h”

double *quadratic(double *factor)
{   static double result[2];
    double delta;
    delta=factor[1]*factor[1]-4*factor[0]*factor[2];
    if(delta<0) return 0;
    delta=sqrt(delta);
    result[0]=(-factor[1]+delta)/(2*factor[0]);
    result[1]=(-factor[1]-delta)/(2*factor[0]);
    return result;
}

void main()

{   double fun[3],*r;
    printf(“Please enter three factors:”);
    scanf(“%lf%lf%lf”,&fun[0],&fun[1],&fun[2]);
    r=quadratic(fun);
    if(r)
        printf(“The solution is: X1=%lf\tX2=%lf\n”,r[0],r[1]);
    else
       printf(“No solution!\n”);
  getch();
}

程序的执行结果是
Please enter three factors:1 3 2
The solution is: X1=-1.000000   X2=-2.000000