I think there may be a problem with my usage of brackets below.

Any ideas on this simple program to find roots of quadratic equation?

many thanks!

include
Code:

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main()
{
char answer;
int a,b,c;
float single_root, root_part1, root_part2;//declaring function variables these
//being different elements of the
//quadratic formula
float root1, root2;
int is_complex;
do
printf("Enter coeficients a b c: ");
scanf("%f %f %f", &a, &b, &c);
is_complex = 0; //(is_complex) function = 0 if a=0
if (a==0)
{
single_root=-1.0*c/b;//stating variables
}
else
{
root_part1 = -1.0*b/(2.0*a); //stating variables
root_part2= b*b-4.0*a*c;
if (root_part2<0.0)
{
is_complex = 1;
root_part2= -1.0*root_part2;//remember this is not equal to,
//this is a directive
}
root_part2=sqrt(root_part2)/(2.0*a);
}
if(a==0.0)
{
Printf("single_root = %f\n ", single_root);//single root case
}
else if (is_complex==1)
{
printf("root 1 = %.2f+%.2f i\n", root_part1, root_part2);
printf("root 1 = %.2f-%.2f i\n", root_part1, root_part2);
}
else
{
root1= root_part1+root_part2;
root2= root_part1-root_part2;
printf("root1 = %.2f", root1);
printf("root2 = %.2f", root2);
}
{
printf("enter next set of coefficients (y/n): ");
scanf(" %c", &answer);
}
while (answer != 'n' && answer != 'N');
scanf("d\n");
exit(0);
}