C++异常处理机制

#include<iostream>
using namespace std;
void testfun(int age)
{
    try
    {
        if(age<0)
            throw"请输入学生年龄必须是整数";
        if(age>20)
            throw age;
        cout<<"年龄正常学生年龄是"<<age<<endl;
    }
    catch (int i)
    {
        cout<<"发生异常：学生年龄太大"<<endl;
    }
    catch(const char *message)//cosnt 牢记const char 
    {
        cout<<"发生异常"<<message<<endl;
    }
}
int main()
{
    testfun(12);
    testfun(-9);
    testfun(77);
    return 0;

}

排错机制直接打进函数里面

或者 函数里面只有抛出异常

而 try catch main里面调用

#include <iostream>
using namespace std;
double div(double a,double b)
{
    if(b==0)
        throw b;
    return a/b;
}
int main()
{
    double x,y,result;
    cout<<"input two numbers:"<<endl;
    while(cin>>x>>y)
    {
        try
        {
            result=div(x,y);
            cout<<x<<"/"<<y<<"="<<result<<endl;
        }
        catch(double)
        {
            cout<<"error"<<endl;
        }
        cout<<"input two numbers:"<<endl;
    }
    return 0;
}