当我尝试调用指针方法时代码卡住了

Question

I may or may not be dumb, but I don't see any reason why my code should work like this instead of how it's supposed to, but any explanation is welcome, as I'm completely lost in my assignment.

The part where I run into a problem is this part:

In this part, the problem occurs in the inner for in the do while loop, legretegek is a vector<Legreteg*> , viszonyokall is a string, that I give to each simulate method. The problem is, that it only runs for the first i value, after that it fails. And it returns with -1073741819.

And last the Legreteg.cpp which contains only the simulate methods:

#include "Legreteg.h"

using namespace std;

const char zivatar = 'z'; // ozon : - , oxigen : 50% ozon , szendioxid : -
const char napos = 'n'; // ozon : - , oxigen : 5% ozon , szendioxid : 5% oxigen
const char mas = 'm'; // ozon : 5% oxigen , oxigen : 10% szendioxid , szendioxid : -

void Ozon::simulate(char &viszony){
    cout << "eljut az ozon simulateig"<<std::endl;
    double newvastagsag = vastagsag;
    switch (viszony){
        case mas: vastagsag *= 0.95; cout << "mas"; *alakul = Oxigen(newvastagsag*0.05, "Oxigen"); cout << "mas2"; break;
        default: break;
    }
}

void Oxigen::simulate(char &viszony){
    cout << "eljut az oxigen simulateig"<<std::endl;
    double newvastagsag = vastagsag;
    switch (viszony){
        case zivatar: vastagsag *= 0.50; cout << "zivatar"; *alakul =Ozon(newvastagsag*0.50, "Ozon"); cout << "zivatar2"; break;
        case napos: vastagsag *= 0.95; cout << "napos"; *alakul = Ozon(newvastagsag*0.05, "Ozon"); cout << "napos2"; break;
        case mas: vastagsag *= 0.90; cout << "mas"; *alakul = Szendioxid(newvastagsag*0.10, "Szendioxid"); cout << "mas2"; break;
    }
}

void Szendioxid::simulate(char &viszony){
    cout << "eljut a szendioxid simulateig"<<std::endl;
    double newvastagsag = vastagsag;
    switch (viszony){
        case napos: vastagsag *= 0.95; cout << "napos"; *alakul = Oxigen(newvastagsag*0.05, "Oxigen");cout << "napos2"; break;
        default: break;
    }
}

The main part gets as far as generating a new Legreteg* object into *alakul , but after that, the cout I placed behind it for torubleshoot reasons, doesn't get ran anymore, and this is the point when the program returns with -1073741819.

Sorry if it's too much, but I'm completely lost on the problem, and any help is appreciated.

A test input(put this in an input.txt, and write input.txt into the program):

4
z 5
x 0.4
s 3
x 4
mmmmnnznnmm

Answer 1

There are no lines that sets the member variable alakul to values other than nullptr . Then you dereferenced alakul ( nullptr ) in the function simulate() like:

*alakul = Oxigen(newvastagsag*0.05, "Oxigen");

This is wrong.

Instead of this, I guess you wanted to allocate new object and assign that to alakul like

alakul = new Oxigen(newvastagsag*0.05, "Oxigen");

instead of dereferencing alakul there.

Also you may want to define

• Copy constructors
• Assignment operators
• Destructors

to handle the pointer properly on object copying. Be careful not to violate The Rule of Three .