/* June 29, 1998 */
/* Operators to process complex numbers */

#include 
#include 

/* User-defined complex number type */
typedef struct {
        double real, imag;
} complex_t;

/* Function Prototypes */
int scan_complex (complex_t *c);
void print_complex (complex_t c);
void add_complex (complex_t c1, complex_t c2, complex_t *c3);
void subtract_complex (complex_t c1, complex_t c2, complex_t *c3);
void multiply_complex (complex_t c1, complex_t c2, complex_t *c3);
void divide_complex (complex_t c1, complex_t c2, complex_t *c3);
complex_t abs_complex (complex_t c);

/* Driver */
main ()
{
        complex_t com1, com2, csum, cdiff, cprod, cdiv;

        /* Gets two complex numbers */
        printf ("Enter the real and imaginary parts of a complex number\n");
        printf ("separated by a space> ");
        scan_complex (&com1);
        printf ("Enter a second complex number> ");
        scan_complex (&com2);

        /* Forms and displays the sum */
        printf ("\n");
        print_complex(com1);
        printf (" + ");
        print_complex(com2);
        printf (" = ");
	add_complex(com1, com2, &csum);
        print_complex(csum);

        /* Forms and displays the difference */
        printf ("\n\n");
        print_complex(com1);
        printf (" = ");
        print_complex(com2);
        printf (" = ");
	subtract_complex(com1, com2, &cdiff);
        print_complex(cdiff);


	/* Forms and displays the product */
        printf ("\n\n");
        print_complex(com1);
        printf (" * ");
        print_complex(com2);
        printf (" = ");
	multiply_complex(com1, com2, &cprod);
        print_complex(cprod);
 

       /* Forms and displays the division */
        printf ("\n\n");
        print_complex(com1);
        printf (" / ");
        print_complex(com2);
        printf (" = ");
	divide_complex(com1, com2, &cdiv);
        print_complex(cdiv);

       /* Forms and displays the absolute value of the first number */
        printf ("\n\n|");
        print_complex(com1);
        printf ("| = ");
        print_complex(abs_complex(com1));
        printf ("\n");
}
/* Complex number input function returns standard scanning error code   */
/*   1 => valid scan, 0 => error, negative EOF value => end of file     */
int scan_complex(complex_t *c) /* output - address of complex variable to
                                           fill                         */
{
        int status;

        status = scanf ("%lf%lf", &c->real, &c->imag);
        if (status ==2)
                status = 1;
        else if (status != EOF)
                status = 0;
        return (status);
}

/* Complex output function displays value as (a + bi) or (a - bi),      */
/* dropping a or b if they round to 0 unless both round to 0            */
void print_complex(complex_t c) /* input - complex number to display    */
{
        double a, b;
        char sign;

        a = c.real;
        b = c.imag;

	printf("(");

	if (fabs(a) < .005 && fabs(b) < .005) {
		printf("%.2f", 0.0);
	} else if (fabs(b) < .005) {
		printf("%.2f", a);
	} else if (fabs(a) < .005) {
                printf("%.2fi", b);
	} else {
		if (b < 0)
			sign = '-';
		else
			sign = '+';
		printf("%.2f %c %.2fi", a, sign, fabs(b));

	}

	printf(")");
}

/*
 *	Returns sum of complex values c1 and c2
 */
void
add_complex(complex_t c1, complex_t c2, complex_t *c3) /* input - values to 
add */ {

	c3 -> real = c1.real + c2.real;
	c3 -> imag = c1.imag + c2.imag;
}

/*
 *	Returns difference c1 - c2
 */
void
subtract_complex(complex_t c1, complex_t c2, complex_t *c3) /* input 
parameters */ {

	c3 -> real = c1.real - c2.real;
	c3 -> imag = c1.imag - c2.imag;
}

/*
 *	Returns product of complex values c1 and c2
 */
void
multiply_complex(complex_t c1, complex_t c2, complex_t *c3) /* input 
parameters */ {

	c3 -> real = ((c1.real * c2.real) - (c1.imag * c2.imag));
	c3 -> imag  = ((c1.real * c2.imag) + (c1.imag * c2.real));
}

/*
 *	Returns quotient of complex values (c1 / c2)
 */
void
divide_complex(complex_t c1, complex_t c2, complex_t *c3) /* input 
parameters */ {

	c3 -> real = ((c1.real * c2.real) + (c1.imag * c2.imag)) / ((c2.real * 
c2.real) + (c2.imag * c2.imag));
	c3 -> imag = ((c1.imag * c2.real) - (c1.real * c2.imag)) / ((c2.real * 
c2.real) + (c2.imag * c2.imag));
}

/*
 *	Returns absolute value of complex number c
 */
complex_t
abs_complex(complex_t c) /* input parameter */
{
	complex_t cabs;

	cabs.real = sqrt(c.real * c.real + c.imag * c.imag);
	cabs.imag = 0;

	return (cabs);
}

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