My code compiles without any errors, but when i press play unreal crashes

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#1

Hi,
My code compiles perfectly fine but when i press play unreal engine crashes instantly.The error says that it goes out of bounds but i cant see anywhere that would be out of bounds in my code. It would be very much appreciated if someone could tell me why UE is crashing and how i can fix it.

the error from the crash report i think is:
Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:C:\Program Files\Epic Games\UE_4.24\Engine\Source\Runtime\Core\Public\Containers/Array.h] [Line: 614] Array index out of bounds: 0 from an array of size 0.

my code that i have just added is

    int32 Bulls, Cows;
    GetBullCows(Guess, Bulls, Cows);
    PrintLine(TEXT("You have %i Bulls and %i Cows"), Bulls, Cows);



void UBullCowCartridge::GetBullCows(const FString& Guess, int32& BullCount, int32& CowCount) const
{
    BullCount = 0;
    CowCount = 0;

    for (int32 GuessIndex = 0; GuessIndex < Guess.Len(); GuessIndex++)
    {
        if (Guess[GuessIndex] == HiddenWord[GuessIndex])
        {
            BullCount ++;
            continue;
        }

        for (int32 HiddenIndex = 0; HiddenIndex < HiddenWord.Len(); HiddenIndex++)
        {
            if (Guess[GuessIndex] == HiddenWord[HiddenIndex])
            {
                CowCount ++;
            }
        }
    }
}

and in BullCowCartridge.h i added this

	void GetBullCows(const FString& Guess, int32& BullCount, int32& CowCount) const
#2

Your array is empty.

#3

what array? from what i can see, everything i can see has a value to it.

  • Guess is the input, so that is the only thing that can be empty at the point of set up game.

  • Hidden word is chosen from begin game. but i know that it chooses a word as if i comment everything out that i wrote from this lecture then it chooses a word from HiddenWordList at random

  • both BullCount and CowCount are set to 0

I feel like i’m missing something obvious but i don’t know what

#4

What’s your begin play and everything it calls?

#5

This is my whole code

void UBullCowCartridge::BeginPlay() // When the game starts
{
    Super::BeginPlay();

    Isograms = GetValidWords(Words);
    SetupGame();
}

void UBullCowCartridge::OnInput(const FString& Input) // When the player hits enter
{
    if(bGameOver)
    {
        ClearScreen();
        SetupGame();
    }
    else
    {
        ProcessGuess(Input);
    }
}

void UBullCowCartridge::SetupGame()
{
    PrintLine(TEXT("Welcome to Bull Cows!"));

    HiddenWord = Isograms[FMath::RandRange(0,Isograms.Num()-1)];
    Lives = HiddenWord.Len();
    bGameOver = false;

    PrintLine(TEXT("Guess the %i letter word!"), HiddenWord.Len());
    PrintLine(TEXT("you have %i Lives"), Lives);
    PrintLine(TEXT("The Hidden Word is: %s.\nIt is %i characters long"), *HiddenWord, HiddenWord.Len());
    PrintLine(TEXT("Type in your guess\nPress enter to continue..."));
}

void UBullCowCartridge::EndGame()
{
    bGameOver = true;
    PrintLine(TEXT("Press enter to play again."));
}

void UBullCowCartridge::ProcessGuess(const FString& Guess)
{
    if (HiddenWord == Guess)
    {
        PrintLine(TEXT("You have won!"));
        EndGame();
        return;
    }
    if (Guess.Len() != HiddenWord.Len())
    {
        PrintLine(TEXT("Sorry, try guessing again!\nYou have %i lives remaining"), Lives);
        PrintLine(TEXT("The hidden word is %i letters long"), HiddenWord.Len());
        return;
    }

    if (!IsIsogram(Guess))
    {
        PrintLine(TEXT("No repeating letters, guess again"));
        return;
    }

    PrintLine(TEXT("You have lost a life"));
    --Lives;
    PrintLine(TEXT("You have %i lives remaining"), Lives);

    if (Lives <= 0 )
    {
        PrintLine(TEXT("You have no lives left"));
        PrintLine(TEXT("The hidden word was %s"), *HiddenWord);
        EndGame();
        return;
    }

    int32 Bulls, Cows;
    GetBullCows(Guess, Bulls, Cows);


    PrintLine(TEXT("You have %i Bulls and %i Cows"), Bulls, Cows);
}

bool UBullCowCartridge::IsIsogram(const FString& Word) const
{
    for (int32 Index = 0; Index < Word.Len(); Index++)
    {
        for (int32 Comparison = Index + 1; Comparison < Word.Len(); Comparison++)
        {
            if (Word[Index] == Word[Comparison])
            {
                return false;
            }
        }
    }
    return true;
}

TArray<FString> UBullCowCartridge::GetValidWords(const TArray<FString>& Wordlist) const
{
    TArray<FString> ValidWords;

    for (FString Word : Wordlist)
    {
        if (Word.Len() >=4 && Word.Len() <= 8 && IsIsogram(Word))
        {
            ValidWords.Emplace(Word);
        }
    }
    return ValidWords;
}

void UBullCowCartridge::GetBullCows(const FString& Guess, int32& BullCount, int32& CowCount) const
{
    BullCount = 0;
    CowCount = 0;

    for (int32 GuessIndex = 0; GuessIndex < Guess.Len(); GuessIndex++)
    {
        if (Guess[GuessIndex] == HiddenWord[GuessIndex])
        {
            BullCount++;
            continue;
        }

        for (int32 HiddenIndex = 0; HiddenIndex < HiddenWord.Len(); HiddenIndex++)
        {
            if (Guess[GuessIndex] == HiddenWord[HiddenIndex])
            {
                CowCount++;
                break;
            }
        }
    }
}
#6

And what is the contents of Words?

#7 
#pragma once
#include "CoreMinimal.h"

const TArray<FString> Words =
{
TEXT("a"),
TEXT("ability"),
TEXT("able"),
TEXT("about"),
TEXT("above"),
TEXT("accept"),
TEXT("yourself")
};

There are 1000 terms inbetween, but i’ve just put the beginning and the end

#8

Well everything looks correct to me. Could you try rebuilding by closing Unreal and then deleting the Binaries and Intermediate folder and then trying to open the project again.

1 Like
#9

That has worked! thank you for all the help :slight_smile:

#10

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