Add Value To Hashmap From Pointer

Question

I am trying to add / delete values from a hashmap I created and stored into a void pointer. However the code I have for adding values seems to give me this error: "Unhandled exception at 0x75B5C41F in Project1.exe: Microsoft C++ exception: std::out_of_range at memory location 0x0027F7C0."

The code for this: http://pastebin.com/FPzz05rU So what did I do wrong here and how can I fix it?

More information can be provided if needed.

Thanks for the comment. However I only have a single hashmap which is created here: pastebin.com/mLtxn7J7 The indexes I've tried are 0 and 1, both fail. — FatalSleep
– FatalSleep, Commented Nov 15, 2013 at 14:08
I am pretty sure that the cast is invalid there and you invoke UB by using its result. — PlasmaHH
– PlasmaHH, Commented Nov 15, 2013 at 14:25
I've tried a ton of things to no avail. So how might I fixed the undefined behavior? — FatalSleep
– FatalSleep, Commented Nov 15, 2013 at 14:31

Nox · Accepted Answer · 2013-11-15 15:46:17Z

1

On this line,

 map->at(key).push_back(value);

there is no vector at the key that you provide, so hash_map::at is throwing an std::out_of_range exception. Unlike hash_map::[], hash_map::at does not create a new element in the map if it does not already exist.

answered Nov 15, 2013 at 15:46

Nox

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3 Comments

FatalSleep Over a year ago

So how would I got about adding the new element? I've tried tons of things and still haven't figured it out.

Nox Over a year ago

You can use hash_map::operator[] in place of hash_map::at in your code, if it's OK to automatically insert the value when it doesn't exist, or you can use hash_map::insert before calling StrVectorMap_AddValue.

FatalSleep Over a year ago

Ah that rocks, using the operator[] worked perfectly!

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