c++的运算符重载中涉及的精度检查问题

//实数计算类的运算符重载

#include<iostream.h>
#include<stdlib.h>
#include<math.h>

class Real
{
public:
Real(int a=0){ value=a; }
friend Real operator+(const Real & i1,const Real & i2);
friend Real operator-(const Real & i1,const Real & i2);
friend Real operator*(const Real & i1,const Real & i2);
friend Real operator/(const Real & i1,const Real & i2);
double GetValue()const;
private:
double value;

};

Real operator+(const Real & i1,const Real & i2) //重载加法运算符
{

double temp=i1.value+i2.value;
if( temp<3.4e38 && temp>-3.4e38) return Real(temp);
else
{ cout<<"\nData overflow!\n"<<endl; //溢出处理--退出程序
abort();
}

}
double Real::GetValue()const
{ return value; }