C++笔记（二十二）异常

#pragma once
#include<iostream>
#include<exception>
using std::cout;
using std::endl;
//异常类，继承exception
class Exception:public std::exception
{
public:
    Exception(const char *s);
};

#include "Exception.h"
#include<cstdlib>
#include<string>


Exception::Exception(const char *s):exception(s) {}

double test(double a, double b);
double test1(double a, double b);

int main() {
    double a = 1;
    double b = -1;
    try
    {
        double c = test(a, b);
    }
    catch (const char *s)
    {
        cout << s << endl;
    }

    try
    {
        double d = test1(a, b);
    }
    catch (std::exception &e)
    {
        cout << e.what() << endl;
    }


    return 0;
}

double test(double a, double b) {
    if (a == -b)
    {
        throw "arguments error!";
    }
    return a * b / (a + b);
}

double test1(double a, double b) {
    if (a == -b)
    {
        throw Exception("errors");
    }
    return a * b / (a + b);
}

输出结果：

arguments error!
errors