How to access struct type 2d Array in another class

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VS2010

Hi, i have created a 2D array from a struct and below is my code.

C#

class RangeValues
{

public:
    
    
     struct RangeStruct{

        int LabelNo;
        double MinValue;
        double MaxValue;
    };
RangeValues(void);
~RangeValues(void);
RangeStruct MyRangeArray[2][88];
};

i have initialized values in RangeValues.cpp class and it works fine...

Now i want to access MyRangeArray from a different class..

C++

RangeValues range;
double LabelValue = range.MyRangeArray[0][1].LabelNo;

But when i print the value it gives something like a big negative number.

ex:

VB

LabelValue  -858993460.00000000

But it shoul equals to 1..(MyRangeArray[0][1].LabelNo contains number 1)

What is wrong with my code? Thank you..

Posted 19-Aug-13 3:40am

Dilan Shaminda

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max_nowak 19-Aug-13 9:47am

please post your initialization code

Dilan Shaminda 19-Aug-13 9:54am

void RangeValues::LoadRangeValues(const char *range_file_name)
{
ifstream RangeFile(range_file_name);
string line = " ";
string Token;
int number_of_lines = 0;
getline(RangeFile,line); // avoid the first line
getline(RangeFile,line); // avoid the second line

while(getline(RangeFile,line))
{
stringstream ss(line); // Insert the string into a stream

vector<string> tokens;
while (ss >> line)
{
tokens.push_back(line);
}

char *token_string_0 = new char[tokens[0].length() + 1];
strcpy(token_string_0, tokens[0].c_str());
MyRangeArray[MainIndexValue][count].LabelNo = atoi(token_string_0);
char *token_string_1 = new char[tokens[1].length() + 1];
strcpy(token_string_1, tokens[1].c_str());
MyRangeArray[MainIndexValue][count].MinValue = atof(token_string_1);
char *token_string_2 = new char[tokens[2].length() + 1];
strcpy(token_string_2, tokens[2].c_str());
MyRangeArray[MainIndexValue][count].MaxValue = atof(token_string_2);

count++;
}
MainIndexValue++;
count = 0;
}

max_nowak 19-Aug-13 10:01am

Are you sure this method is called from somewhere within the constructor of your RangeValues object? Because the class above does not even feature a method called 'LoadRangeValues'

Dilan Shaminda 19-Aug-13 10:05am

yes, there is a method called LoadRangeValues in the class.i just put struct and my array part only.i have printed the values of MyRangeArray values inside RangeValues class and it prints values correctly..Problem is when i access the MyRangeArray from a different class

Stefan_Lang 19-Aug-13 11:13am

Ok, if from inside the values are ok, then maybe you haven't passed your RangeValues object to the other class correctly? Are you sure the object you are trying to read from is the one you initialized? If you use a pointer to pass the object, is that pointer correct from inside the other class?

Dilan Shaminda 19-Aug-13 11:22am

RangeValues range;
double LabelValue = range.MyRangeArray[0][1].LabelNo;

this is how i tried to access MyRangeArray values from another class..is this correct ? Thanks

Richard MacCutchan 19-Aug-13 11:38am

You just created a new instance of your class with no values in it, so LabelValue will now contain garbage.

Stefan_Lang 20-Aug-13 2:32am

That isn't what I asked. I've seen and read and understood those two lines before. However, a lot of important information is missing:

1. Where and when do you call your initialization method LoadRangeValues ?
2. Are those lines really all there is, and, more importantly, are they in the same place, or are you passing the object to another function. I. e. is the object you query really the same that you initialize?

Going by these two lines alone I'd say you don't initialize your object, and therefore the values you read are random junk.

Stefan_Lang 19-Aug-13 9:54am

In your code above there is no initialization, just the declaration of the RangeValues variable and then immediately reading the LabelNo value. Did you accidentally overwrite the RangeValues variable with a new local instance? If not, did you pass the initialized instance correctly?

Dilan Shaminda 19-Aug-13 10:06am

Hi, i read MyRangeArray values after assigning some values to it..i have put that function above in my comment..

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H.Brydon · Accepted Answer · 2013-08-19T06:37:00

Solution 1

You can use your code pretty much as is. You are dealing with uninitialized data on the stack. You should add a constructor for your struct, and initialize all values in the struct to something. When you instantiate your class on the stack, the array will have consistent values.

Posted 19-Aug-13 6:37am

H.Brydon