I got carried a bit away and wrote the code

[fareeds]

bool UBullCowCartridge::IsIsogram(FString Guess){
    char ch=Guess[0];
    int32 arr[26]={};
    for(int32 i=0;i<Guess.Len();i++){
        if(Guess[i]>='a'&&Guess[i]<='z'){
            arr[Guess[i]-'a']++;
        }else if(Guess[i]>='A'&&Guess[i]<='Z'){
            arr[Guess[i]-'A']++;
        }else{
            return false;
        }
    }
    for(int32 i=0;i<26;i++){
        if(arr[i]>1)return false;
    }
    return true;
}

Run:

[Kevin-Brandon]

Now that’s what I am talking about!