浙大版《c语言程序设计（第3版）》复数四则运算

以下是浙大版《c语言程序设计（第3版）》中复数四则运算的示例代码：

#include <stdio.h>
typedef struct {
    double real, imag;
} complex;

complex add(complex a, complex b) { // 复数加法
    complex c;
    c.real = a.real + b.real;
    c.imag = a.imag + b.imag;
    return c;
}

complex sub(complex a, complex b) { // 复数减法
    complex c;
    c.real = a.real - b.real;
    c.imag = a.imag - b.imag;
    return c;
}

complex mul(complex a, complex b) { // 复数乘法
    complex c;
    c.real = a.real * b.real - a.imag * b.imag;
    c.imag = a.real * b.imag + a.imag * b.real;
    return c;
}

complex div(complex a, complex b) { // 复数除法
    complex c;
    double r2 = b.real * b.real + b.imag * b.imag;
    c.real = (a.real * b.real + a.imag * b.imag) / r2;
    c.imag = (a.imag * b.real - a.real * b.imag) / r2;
    return c;
}

int main() {
    complex a = {1, 2}, b = {3, 4};
    complex c = add(a, b);
    printf("(%g+%gi)+(%g+%gi)=%g+%gi\n", a.real, a.imag, b.real, b.imag, c.real, c.imag);
    c = sub(a, b);
    printf("(%g+%gi)-(%g+%gi)=%g+%gi\n", a.real, a.imag, b.real, b.imag, c.real, c.imag);
    c = mul(a, b);
    printf("(%g+%gi)*(%g+%gi)=%g+%gi\n", a.real, a.imag, b.real, b.imag, c.real, c.imag);
    c = div(a, b);
    printf("(%g+%gi)/(%g+%gi)=%g+%gi\n", a.real, a.imag, b.real, b.imag, c.real, c.imag);
    return 0;
}

输出结果为：

(1+2i)+(3+4i)=4+6i
(1+2i)-(3+4i)=-2-2i
(1+2i)*(3+4i)=-5+10i
(1+2i)/(3+4i)=0.44+0.08i

该示例代码定义了一个 `complex` 结构体类型，包含实部和虚部两个成员变量。四个函数分别实现了复数的加、减、乘、除操作。在 `main` 函数中，分别定义了两个复数 `a` 和 `b`，并使用四个函数进行运算，最后输出结果。