Writing a Client File in C

I am trying to write a program using abstract data types in c for basic polynomial operations.

So far I have

.h file

#ifndef Polynomials_ADT_h
#define Polynomials_ADT_h

#include <stdlib.h>

typedef struct poly *Polynomial;

void printPoly(Polynomial);

Polynomial setTerm(int, int);

Polynomial sumPoly(Polynomial, Polynomial);

Polynomial multiPoly (Polynomial, Polynomial);

float evalPoly (Polynomial, float);



#endif

.c implementation file

#include "Polynomials ADT.h"
#include <stdlib.h>


struct poly {int n; int *a;};
Polynomial setTerm (int coeff, int exponent)
{
    int i;
    Polynomial d = malloc(sizeof*d);
    d->a = malloc((exponent+1)*(sizeof(int)));
    d->n = exponent+1;
    d->a[exponent] = coeff;
    for(i=0; i<exponent; i++)
        d->a[i] = 0;
    return d;

}
Polynomial sumPoly(Polynomial r, Polynomial s)
{
    int i; Polynomial d;
    if(r->n < s-> n)
    {
        d = r;
        r = s;
        s = d;

    }

    for (i=0; i< s->n; ++i)
    {
        s-> a[i]+= s-> a[i];
    }

    return s;
}

Polynomial multiPoly (Polynomial s, Polynomial r)
{
    int i, j;
    Polynomial d = setTerm(0, (r->n-1)+ (s->n-1) );
    for (i=0; i < r->n; ++i)
    {
        for(j = 0; j< s->n; ++j)
        {
            d-> a[i+j]+= r->a[i]*s->a[j];
        }
    }
    return d;
}

float evalPoly (Polynomial r, float x)
{
    int i;
    double d = 0.0;
    for (i = r->n-1; i>=0; i--)
    {
        d = d*x + r-> a[i];
    }
    return d;
}

and finally I am stuck on creating my test file to test my logic

this is what I have for the main function so far:

#include <stdio.h>
#include <stdlib.h>
#include "Polynomials ADT.h"


int main()
{

    Polynomial d = setTerm(1,2);

    Polynomial r = setTerm(1,2);

    a = sumPoly(d,r);

    printf("%d",a);


}

My question is how do I print my results to see if my implementation file works? I am not sure of how to display the results of my functions such as sumPoly, multiPoly and evalPoly....please help!