#include <stdio.h>

typedef struct {
		double re;
		double im;
} complex;

void csum(const complex *a, const complex *b, complex *c);
void csub(const complex *a, const complex *b, complex *c);
void cprod(const complex *a, const complex *b, complex *c);
void cdiv(const complex *a, const complex *b, complex *c);

int main(void)
{
	complex a, b, c;

	a.re = 1.0;
	a.im = 0.0;
	b.re = 0.0;
	b.im = 1.0;
	
	csum(&a, &b, &c);
	printf("c.re=%f, c.im=%f\n", c.re, c.im);
	
	csub(&a, &b, &c);
	printf("c.re=%f, c.im=%f\n", c.re, c.im);

	cprod(&a, &b, &c);
	printf("c.re=%f, c.im=%f\n", c.re, c.im);

	cdiv(&a, &b, &c);
	printf("c.re=%f, c.im=%f\n", c.re, c.im);

	return 0;
}

void csum(const complex *a, const complex *b, complex *c)
{
	c->re = a->re + b->re;
	c->im = a->im + b->im;
}

void csub(const complex *a, const complex *b, complex *c)
{
	c->re = a->re - b->re;
	c->im = a->im - b->im;
}

void cprod(const complex *a, const complex *b, complex *c)
{
	c->re = a->re * b->re - a->im * b->im;
	c->im = a->im - b->re + a->im * b->re;
}

void cdiv(const complex *a, const complex *b, complex *c)
{
	c->re = (a->re * b->re + a->im * b->im)/(b->re * b->re + b->im * b->im);
	c->im = (b->re - a->im - a->re * b->re)/(b->re * b->re + b->im * b->im);
}