Terminate called after throwing an instance of std::exception

Question

I'm new to exceptions and I tried to improve a solution for question that one of my friend had in a job interview.

My friend was asked to build a program which will get 2 arrays and find a number, which if we divide it by the members of the first array, we will get a matching leftover of the second array.

Can I use std::exception without any inheriting classes in this case?

THE CPP FILE

#include <iostream>
#include <exception>
#include "FindNumber.h" 


Finder::Finder() : m_num(0)
{}


int Finder::FindFirst(int* _divided, int* _leftOver, int _size)
{
    int indx = 0;

    while(indx < _size)
    {

        if (!_divided[indx])
        {
            throw("Can not divide by zero!!");
        }

        if (m_num % _divided[indx] != _leftOver[indx])
        {
            ++m_num;
            FindRest(_divided, _leftOver, _size);
            indx = 0;
        }

        ++indx;
    }

    return m_num;
}


int Finder::FindRest(int* _divided, int* _leftOver, int _size)
{
    int indx = 0;

    for(;;)
    {
        if (!_divided[indx])
        {
            throw("Can not divide by zero!!");
        }

        if (m_num % _divided[indx] != _leftOver[indx])  
        {
            ++m_num;
        }
        else
        {
            break;
        }
    }

    return m_num;
}

THE TEST UNIT

#include <cstdio>
#include <iostream>
#include "FindNumber.h"
#include "mu_test.h"

#define SIZE 5

/****************************** FN_check1 ******************************/
UNIT(FN_check1) 

    int divided [SIZE] = {0, 4, 5, 6, 7};
    int leftOver [SIZE] = {2, 0, 3, 2, 1};
    Finder find1;

    try
    {   
        ASSERT_THAT(6 != find1.FindFirst(divided, leftOver, SIZE));
        ASSERT_THAT(8 == find1.FindFirst(divided, leftOver, SIZE));
    }
    catch(std::exception& e)
    {
        std::cout << e.what();
    }

END_UNIT


/****************************** FN_check2 ******************************/
UNIT(FN_check2) 

    int divided [SIZE] = {6, 12, 8, 10, 7};
    int leftOver [SIZE] = {0, 0, 4, 2, 5};
    Finder find1;


    ASSERT_THAT(6 != find1.FindFirst(divided, leftOver, SIZE));
    ASSERT_THAT(12 == find1.FindFirst(divided, leftOver, SIZE));

    std::cout << find1.FindFirst(divided, leftOver, SIZE) << std::endl;

END_UNIT




TEST_SUITE(FindNumber_test)

    TEST(FN_check1)
    TEST(FN_check2)

END_SUITE

Thanks in advance...

userSeventeen userSeventeen · Accepted Answer · 2019-02-22T13:28:23

Lines like below that you use to throw exceptions:

if (!_divided[indx]) {
    throw("Can not divide by zero!!");
}

You are throwing a string (actually a const char*), which obviously does not inherit from std::exception which you try to catch later on. You could try to throw std::runtime_error("Can not divide by zero!!"); or throw a std::invalid_argument, whichever is more appropriate for each situation. Why the exception occurs seems to be known by the error message.

Terminate called after throwing an instance of std::exception

1 Answers