异常处理

例一：

#include<iostream>using namespace std;//double div(double x, double y) throw(int, double) //限制抛出的类型，如不匹配，直接抛给内核//double div(double x, double y) throw() //直接抛给内核double div(double x, double y) //没有限制{    if(y==0)        throw "exception";    cout<<"div(x, y)"<<endl;    return x/y;}void main(){    try{        try{            divison(5, 0);        }        catch (int errcode){            cout << "div can't be 0!" << errcode << endl;            //throw 10;            throw;//继续抛一样的        }        catch (double errcode){            cout << "div can't be 0.0!" << errcode << endl;            //throw 10.0;            throw;        }        catch (...){//其他类型异常            cout << "div can't be 0.0!" << endl;            throw;        }    }    catch (int errcode){        cout << "div can't be 0.0!" << errcode << endl;    }    catch (double errcode){        cout << "div can't be 0.0!" << errcode << endl;    }    catch (...){//其他类型异常        cout << "div can't be 0.0!" << endl;    }    cout << "main end!" << endl;}

例二：异常嵌套

#include<iostream>using namespace std;double division(double x, double y) throw(){    if (y == 0)        //throw  "exception";        throw 100;    cout << "div(x,y)" << endl;    return x / y;}void fun(){    try{        division(5, 0);    }    catch (int errCode)    {        cout << "first exception, " << errCode << endl;        throw;    }}int main(void){    try{        fun();    }    catch (int errCode){        cout << "catched exception, " << errCode << endl;    }    catch (double errCode){        cout << "catched exception, " << errCode << endl;    }    catch (...){//其他类型异常        cout << "catched ..." << endl;    }    cout << "main end" << endl;    return 0;}

例三：异常类

#include<iostream>using namespace std;class MyException{    public:        MyException(string errInfo="unknown", int errNo=0)            :errInfo(errInfo), errNo(errNo)        {            cout<<"MyException()"<<endl;        }        ~MyException()        {            cout<<"~MyException()"<<endl;        }        MyException(const MyException &)        {            cout << "MyException(MyException&)" << endl;        }        void out()        {            cout<<"no:"<<errNo<<", info:"<<errInfo<<endl;        }    private:        string errInfo;        int errNo;};void fun(int code){    if(code==110)    {        //throw MyException("terrist", 110);//首选,保证唯一性，且在传递时不会丢失        MyException temp("terrist", 110);        throw temp;    }    if(code==120)    {        MyException *MyEx=new MyException("help", 120);        throw MyEx;    }    if(code==119)    {        MyException MyEx("fire", 119);        throw &MyEx; //不要返回局部变量的地址    }}main(){    cout<<"please input errnun:";    int code;    cin>>code;    try{        fun(code);    }/*catch(MyException &MyEx)   //类型为MyException的异常将会-->    {        cout<<"reference"<<endl;        MyEx.out();    }*/catch(MyException MyEx)    //-->为MyException更早的处理者所捕获    {        cout<<"value"<<endl;        MyEx.out();    }catch(MyException *MyEx)    {        cout<<"pointer"<<endl;        MyEx->out();        //对于120而言才需要；        delete MyEx;    }}