typedef struct
{
 double real;
 double imag;
} complex;

//复数乘法
complex X_complex(complex a, complex b)
{
 complex temp;

 temp.real = a.real * b.real - a.imag * b.imag;
 temp.imag = b.imag * a.real + a.imag * b.real;

 return temp;
}

int main(int argc, char *argv[])
{
 complex a,b,c;

 a.real = 2;
 a.imag = 3;
 b.real = 4;
 b.imag = 5;

 c = X_complex(a,b);//结构体可以作为返回值，然后赋值给另一个相同结构体的变量
 cout