C++ After Function Call and Function Completion, Game Crashes Entirely - c++

Question

I've been having an issue with a game I've been making in my C++ game programming class for school. For some reason, after calling a function which I'm using to manage the inventory based stuff, the function seems to complete and work (I think this because I put in cout commands at the end of it and they printed correctly, also the function runs twice in a row, and they both run), my entire game crashes and doesn't reach the next line. I tried commenting out all the code in the function and it still crashed. I commented out the function calls and it worked, but I still can't tell what is wrong with it. I'll put the code for the function and the section were I make the calls:
string inventoryFunction(int h, string ab)
{
if(h == 1)
inventory.push_back(ab);
else
if(h == 2)
{
for(int i=0; i < inventory.size(); i++)
{
if(inventory[i] == ab)
inventory[i].erase();
}
}
else
if(h == 3)
{
cout << inventory[0];
for(int i=1; i < inventory.size(); i++)
cout << ", " << inventory[i];
}
}
The function call:
if(answer.find("village") != string::npos)
{
cout << endl;
cout << "While looking around your village,\nyou found a stone sword and a cracked wooden shield!" << endl;
inventoryFunction(1, "stone sword");
inventoryFunction(1, "cracked wooden shield");
cout << "Would you like to set off on your adventure now?" << endl;
cin >> answer2;
capitalizeLower(answer2);

Answer 1

Not sure there's anything there likely to cause a crash, my advice would be to single-step your code in the debugger to see where it's falling over. It's quite possible the bug is somewhere totally different and it's just being exacerbated by the function calls modifying the vector.
That's the nature of bugs unfortunately, you can never really tell where they're actually coming from without looking closely :-)
However, there are a couple of issues with the code that I'd like to point out.
First, with regard to:
inventory[i].erase();
That doesn't do what you think it does. inventory[i] is the string inside your vector so it's simply erasing the string contents.
If you want to remove the string from the vector, you need something like:
inventory.erase (inventory.begin() + i);
Second, I'd tend to have three separate functions for addToInventory, removeFromInventory and listInventory.
It seems a little ... unintuitive ... to have to remember the magic values for h to achieve what you want to do, and there's no real commonality in the three use cases other than access to the inventory vector (and that's not really reason enough to combine them into the same member function).
On top of that, your function appears to be returning a string but you have no actual return statements and, in fact, none of the three use cases of your function require anything to be passed back.
The signature is better off as:
void inventoryFunction(int h, string ab)
In terms of the second and third points above, I'd probably start with something like:
void addToInventory (string item) {
inventory.push_back(ab);
}
void removeFromInventory (string item) {
for (int i = 0; i < inventory.size(); i++) {
if (inventory[i] == ab) {
inventory.erase (inventory.begin() + i);
break;
}
}
void listInventory () {
cout << inventory[0];
for (int i = 1; i < inventory.size(); i++)
cout << ", " << inventory[i];
}
You may also want to look into using iterators exclusively for the second and third functions rather than manually iterating over the collection with i.
It'll save you some code and be more "C++ic", a C++ version of the "Pythonic" concept, a meme that I hope will catch on and make me famous :-)

Answer 2

So by changing the inventoryFunction to a void function like #Retired Ninja said, the crash has stopped occurring and now the program is working great.
Also, #paxdiablo pointed out that I was using the inventory[i].erase() thing incorrectly, so thanks a bunch to him, because now I won't have to come back on here later to try to fix that :D

Answer 3

string inventoryFunction(int h, string ab)
should return a string but does not have any return statements. Of course it works, after you change it to a void function, which correctly does not return anything. Interesting is, that you are able co compile this code without an error - normally a compiler would show you this problem.