習題9-2 計算兩個復數之積（15 分）

本題要求實現一個計算復數之積的簡單函數。

函數接口定義：

struct complex multiply(struct complex x, struct complex y);

其中struct complex是復數結構體，其定義如下：

struct complex{
    int real;
    int imag;
};

裁判測試程序樣例：

#include <stdio.h>

struct complex{
    int real;
    int imag;
};

struct complex multiply(struct complex x, struct complex y);

int main()
{
    struct complex product, x, y;

    scanf("%d%d%d%d", &x.real, &x.imag, &y.real, &y.imag);
    product = multiply(x, y);
    printf("(%d+%di) * (%d+%di) = %d + %di\n", 
            x.real, x.imag, y.real, y.imag, product.real, product.imag);

    return 0;
}

/* 你的代碼將被嵌在這里 */

輸入樣例：

3 4 5 6

輸出樣例：

(3+4i) * (5+6i) = -9 + 38i

#include <stdio.h>

struct complex{
    int real;
    int imag;
};

struct complex multiply(struct complex x, struct complex y);

int main()
{
    struct complex product, x, y;

    scanf("%d%d%d%d", &x.real, &x.imag, &y.real, &y.imag);
    product = multiply(x, y);
    printf("(%d+%di) * (%d+%di) = %d + %di\n", 
            x.real, x.imag, y.real, y.imag, product.real, product.imag);

    return 0;
}

/* 你的代碼將被嵌在這里 */

struct complex multiply(struct complex x, struct complex y)
{
    struct complex result;//struct complex相當於int 
    result.real=x.real*y.real-x.imag*y.imag;
    result.imag=x.real*y.imag+x.imag*y.real;
    return result;
}