Creating a global array of structs

Question

For a project I am working on I need to have a global array of entry structs. I am having trouble though because I can't allocate memory until while running my program I determine the size of a file. The overall goal of this project is to create a word reference. So far how I am doing it is:

struct info{
   //stores the specific character
   std:: string c;
   //stores the amount of times a word has come up in the file
   float num;
}
info info_store[];

This project is to learn about arrays so I need to use an array

Use an std::vector.

Chris Kitching
– Chris Kitching

2018-02-09 04:52:06 +00:00
Commented Feb 9, 2018 at 4:52 — Chris Kitching
– Chris Kitching, Commented Feb 9, 2018 at 4:52
I forgot to mention I need to use an array

Darkhail
– Darkhail

2018-02-09 05:03:16 +00:00
Commented Feb 9, 2018 at 5:03 — Darkhail
– Darkhail, Commented Feb 9, 2018 at 5:03
... Why? Is this homework or something?

Chris Kitching
– Chris Kitching

2018-02-09 05:03:54 +00:00
Commented Feb 9, 2018 at 5:03 — Chris Kitching
– Chris Kitching, Commented Feb 9, 2018 at 5:03

Picaud Vincent · Accepted Answer · 2018-02-09 05:10:29Z

1

You can:

- use new/delete[]

info* p_array=new info[100];  // create an array of size 100

p_array[10].num;  // member access example

delete[] p_array; // release memory

- use std::unique_ptr

std::unique_ptr<info[]> array(new info[size]);

-> The advantage is that your memory is automatically released when array is destroyed (no more delete[])

answered Feb 9, 2018 at 5:10

Picaud Vincent

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Siborgium · Accepted Answer · 2018-02-09 05:06:27Z

0

First of all, use std::vector or any other STL container.

Second, you can use dynamic arrays.

auto length = count_structs(file);
auto data = new info[length];

Something like this. Then just fill this array.

Ohh, and make sure you have delete [] data to prevent memory leaks.

answered Feb 9, 2018 at 5:06

Siborgium

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