how to make a pointer to an array? or how to return an array?

[Recluse]

Hello I am currently making a program that reads from a text file and a bunch of questions and answers and puts them on screen for a practice test for my class.
My teacher is lazy and for my ISP had me make a program that he can test future classes with.

anyways I have a class that reads the file and I am having trouble returning the array of strings that I get from reading the file. I have tried making a pointer to the array so that I can access it from my main function but I am having problems.

When I try this it gives me an error.. cannot convert int[3] to *int
which obviously means I cant make a pointer to the array. But I am wondering if I am doing it wrong or there is a different way.

This is just some practice code.. not my program :p

#include <iostream>

using namespace std;

int main()
{
    int fish[3] = {5,2,3};
    cout<<fish[0]<<','<<fish[1]<<','<<fish[2]<<endl;
    int *tuna = &fish;
    cout<<tuna<<endl;
}

[therockon7throw]

when you make a pointer to an array you should define the element, if you dont the pointer points to the first element of array, in your case :->

 int *tuna = fish;
 cout<<*tuna<<endl;

if you want to access other elements you may use tuna[ index ] or *( tuna + index )

[Recluse]

I want to be able to read the array from my main function. when the array was made in a different class. without having to make a for/while loop or returns. and was wondering if this was possible.

[Zhuge]

Can you give a more concrete example of what you talking about? Like a function that has an array you want to do something with?

[Recluse]

ok this is my code.

void Answers::getString()
{

    string str[getLine()];
    int counter = 0;
    fi.open("test.txt");
    if(fi.good())
    {
        while(!fi.eof())
        {
            getline(fi,str[counter]);
            cout<<str[counter]<<endl;
            counter++;
        }
    }
    fi.close();
}

the getLine() function gets the number of lines in a file.

I want to return the array str to my main function so that I can display it on screen. or do somthing with it in my main function.

[vlad from moscow]

This definition

string str[getLine()];

is invalid because C++ requires that size of array be a constant expression. You can use such construction provided that your function was declared with constexpr specifier.

As for your problem you can allocate dynamically your array and return a pointer to it. The better approach is to use std::vector<std::ctring> defined in the main and pass it by reference to your function.

[Recluse]

it compiles fine and works fine... so its not invalid...
getLine() returns an int. this is the size of the array.
each index in the array represents a line.

heres the code for getLine().

int Answers::getLine()
{
    int lineCount = 0;
    string str;
    fi.open("test.txt");
    if(fi.good())
    {
        while(getline(fi,str))
        {
            lineCount++;
        }
    }
    fi.close();
    return lineCount;
}

could you explain that second part more clearly please. maybe some example code?

[therockon7throw]

The easies way to solve your problem is to use stl collection, such as vector where you can add new element or remove an element.
a simple example for your case ->

void Answers::getString( vector<string>& list)
{

   
  String str;
    fi.open("test.txt");
    if(fi.good())
    {
        while(!fi.eof())
        {
            getline(fi,str);
            cout<<str<<endl;
            list.push_back(str);
        }
    }
    fi.close();
}

your main may be some thing like ->

int main(){
  vector<string> list;
  getString(list); 

 // here you can do whatever you wish with your list of strings
// for instance
        for(int i = 0 ; i < list.size() ; i++){
         cout<<list.at(i)<<endl;
       }
 // or use iterator to do other things

}

[Moschops]

it compiles fine and works fine... so its not invalid...

It is incorrect C++. Your compiler is not quite a C++compiler and lets it through. It's not necessarily a problem, but you should know when you're coding in C++ and when you're not.

[Recluse]

i use the GNU GCC compiler what would you call a c++ compiler?

Also i have never used the vector class before.. is there documentation of it on MSDN? or somewhere?

[therockon7throw]

http://www.cplusplus.com/reference/stl/vector/