C++自定义异常类

代码样例：

#include <iostream>

using namespace std;

class illegalParameterValue {
public:
    illegalParameterValue() : message("Illegal parameter value") {};

    illegalParameterValue(char *theMessage) { message = theMessage; };

    void outputMessage() { cout << message << '\n'; }

public:
    string message;

};

int abc(int a, int b, int c) {
    if (a <=  || b <=  || c <= ) {
        throw illegalParameterValue("All parameters should be >0");
    }
    return a + b * c;
}

int main(int argc, char const *argv[]) {
    try {
        cout << abc(, , ) << '\n';
    } catch (illegalParameterValue e) {
        cout << "The parameters to abc were 2, 0, and 4" << '\n';
        cout << "illegalParameterValue exception thrown" << '\n';
        e.outputMessage();
    }

    return ;
}