Programmeren in C/Struct

#include <stdio.h>
#include <conio.h>
 
struct complex 
{
int r;
int i;
};
 
struct complex lees(void);
struct complex som(struct complex a, struct complex b);
struct complex product(struct complex a, struct complex b);
void schrijf(struct complex c);
 
int main (void)
{
	struct complex c1;
	struct complex c2;
	char d;
 
	c1 = lees();
	c2 = lees();
	printf("\nSom=\n");
	schrijf(som(c1,c2));
	printf("\nProduct=\n");
	schrijf(product(c1,c2));
	printf("\n");
 
	d=getch(); /*Pause, zodat je zelf beslist wanneer het venster sluit*/
	return 1;
}
 
struct complex lees(void)
{
	struct complex c;
	printf("Geef een complex getal (vb. 3+5i)\n");
	scanf("%d+%di",&c.r,&c.i);
	return c;
}
struct complex som(struct complex a, struct complex b)
{
	struct complex c;
	c.r = a.r + b.r;
	c.i = a.i + b.i;
	return c;
}
 
struct complex product(struct complex a, struct complex b)
{
	struct complex c;
	c.r = a.r*b.r -  a.i*b.i;
	c.i = a.r*b.i +  a.i*b.r;
	return c;
}
 
void schrijf(struct complex c)
{
	printf(" %d+%di ", c.r, c.i);
}