safe-except_dog

safe.cc

#include <iostream>
#include <algorithm>
#include <vector>
#include <utility>

class T {
public:
    T(const string& value)
        : value(value)
    {
        if (value == "fish")
            throw std::runtime_error("No fish allowed");
    }

    int
    call(int k) {
        if (value == "dog")
            return 4;
        else
            return 3 * k;
    }

private:
    const string value;
};

int main () {
    {
        T* ptr = nullptr;
        try {
            ptr = new T("fish");
        } catch (...) {}

        if (ptr)
            ptr->call(4);
    }

    {
        T* ptr = nullptr;
        try {
            ptr = new T("dog");
        } catch (...) {}

        if (ptr)
            ptr->call(4);
    }

    {
        T* ptr = nullptr;
        try {
            ptr = new T("cow");
        } catch (...) {}

        if (ptr)
            ptr->call(4);
    }
}