CODEWITHSUNDEEP
c++arraysclass
LuisM
LuisM

Reputation: 11

how to make a class function return array and then call and store it in main

In this program I am asked to work with a certain number of values that are stored in a file.txt.

I have a class that has a public function called Absolute_frequency that returns a pointer to an array created in the function called abs_freq[]. My problem is that I now need to save this array into another array in my main. 

int *Data::Absolute_frequency() {

/*Here I created 2 arrays that store values representing max and min limit 
of certain intervals (eg. 0 to 20, 21 to 40, 41 to 60, etc...)

And then I run my code thru each of these intervals and count how many 
values are in them, and store it in abs_freq[]:*/

int *abs_freq=new int [num_intervals]();  

for (int j = 0; j < num_values; j++)
{
    for (int i = 0; i < num_intervals; i++)
    {
        if (values[j] >= intervals_min[i] && values[j]<=intervals_max[i])
        {
            abs_freq[i]++;
        }
    }
}

return abs_freq;
}

From what I have tested, the array abs_freq[i] is storing what is suposed, now my problem is that I need to pass this array into my main(). I tried something like this but as I was expecting, it only passed the 1st value of abs_freq:

int main(){

Data data;
int *absolute_freq = new int[num_intervals]();
...
   for (int i = 0; i < num_intervals; i++)
   {
      absolute_freq[i] = *data.Absolute_frequency();
   }

   for (int i = 0; i < num_intervals; i++)
   {
      printf("Absolute frequency interval %d: %d \n", i+1,absolute_freq[i]);
   }
   ....
}

How can I store the entire array instead of just the 1st value?

Upvotes: 0

Views: 54

Answers (2)

Some programmer dude
Some programmer dude

Reputation: 409166

You do it by having a pointer variable in the main function, and initialize it with the pointer returned by the function:

int* absolute_freq = data.Absolute_frequency();

Remember that once you're done with the array you have to delete[] it.

Upvotes: 3

Stephan Lechner
Stephan Lechner

Reputation: 35154

In your code for (int i = 0; i < num_intervals; i++) { absolute_freq[i] = *data.Absolute_frequency() ..., you call function Absolute_frequency again and again, each time creating a new array of integers (which you do not free). Further, *data.Absolute_frequency() is equivalent to data.Absolute_frequency()[0], i.e. it always gives you the first entry in the array.

Not sure what you actually have to achieve; but I suppose the following code would be better:

int *absolute_freq = data.Absolute_frequency();
for (int i = 0; i < num_intervals; i++)
{
   printf("Absolute frequency interval %d: %d \n", i+1,absolute_freq[i]);
}
delete[] absolute_freq;

Upvotes: 0

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