Program to find roots of polynomial equation

#include<stdio.h>
#include<conio.h>
#include<math.h>
void main()
{
    float a,b,c,x1,x2,d;
    clrscr();
    printf("enter the values of a,b,c");
    scanf("%f%f%f",&a,&b,&c);
    d=b*b-4*a*c;
    if(d>0)
    {
        x1=(-b+sqrt(d))/2;
        x2=(-b-sqrt(d))/2;
        printf("roots are x1,x2 =%f,%f",x1,x2);
    }
    else if(d==0)
    {
        x1=x2=-b/(2*a);
        printf("roots are x1,x2 =%f,%f",x1,x2);
    }
    else
    {
        printf("roots are imaginary");
    }
    getche();
}