I'd like to ask you a multiplicationcrying

#include<stdio.h>
#define MAX_DEGREE 10
typedef struct{
 int degree;
 float coef[MAX_DEGREE];
}polynomial;
polynomial poly_product(polynomial A,polynomial B)
{
 int i,j;
 polynomial C,Tmp;
 int degree_a=A.degree;
 int degree_b=B.degree;
 C.degree=A.degree+B.degree;
  for(i = 0; i < MAX_DEGREE; i++)
   {
      C.coef[i] = 0;
   }
 for(i=0;i<=degree_a;i++){
  for(j=0; j<=degree_b;j++){
   C.coef[i+j]+=A.coef[i]*B.coef[j];
  }
 }
 return C;
}
void main(void)
{ 
 polynomial a = { 5, {10, 0, 0, 0, 6, 3} };
 polynomial b = { 4,     {1, 0, 5, 0, 7} };
 polynomial c;
 c = poly_product(a,b);
 int i;
 printf("order: %d difference\n", c. degree);
 for(i=c.degree;i>0;i--)
 {
  printf ("%d-order coefficient: %".2lf\n",i,c.coef[i]);
 }
 printf ("constant: %").2lf\n",c.coef[0]);  
}