#include
using namespace std;
struct complex{　
double real, imag;　
complex(double = 0.0, double = 0.0);
}
complex：complex(double r, double i)
{
　real = r;　imag = i;
}
inline ostream& operator<<(ostream &os, const complex &c)
{　
os << ‘(’ << c.real << ‘,’ << c.imag << ‘)’;
return os;
}
inline complex operator+(const complex &c1, const
complex &c2)
{　return complex(c1.real+c2.real,c1.imag+c2.imag);
}
复数加法运算
关键字operator是函数名的一部分。为实现两个复数的加法可以将operator+定义为全局类型。(重载加法运算)
关键字内联（inline）是提示编译器要把相应的代码“内联”。
complex operator+(const complex &c1,const complex &c2)
{　
complex r;　
r.real=c1.real+c2.real;　
r.imag=c1.imag+c2.imag;　
return r;
｝