Thread: Getting Struct Variables

I've tried posting this before, but I wasn't very clear.

I have two cpp files, and two headers.

both the cpp files include the headers of the other cpp files, so every function in each cpp can be used by the other cpp.

In one header, I made a struct with a floating point in it.

I gave the floating point a value in cpp file number 1.

I want to access that floating opint in cpp file number 2, but how do I tell it where to find the value?

I defined a struct of the same type in cpp number 2, but I need to give struct.float a value, and that value has to be the same as the one in cpp number 1.

It sounds like you want a global variable:

Code:

// header1.h
#ifndef HEADER1_H
#define HEADER1_H

struct test {
  double f;
};

extern test t;

#endif

Code:

// header2.h
#ifndef HEADER2_H
#define HEADER2_H

void foo();

#endif

Code:

// header1.cpp
#include "header1.h"

test t = {0};

Code:

// header2.cpp
#include "header1.h"
#include "header2.h"

void foo() {
  t.f = 1.5;
}

Code:

// main.cpp
#include <iostream>
#include "header1.h"
#include "header2.h"

int main() {
  foo();
  std::cout << t.f << '\n';
  return 0;
}

He says I should use classes, not structs.

Structures are classes with default public access. Your friend isn't making any sense. Changing the struct to a class wouldn't make any difference because you can use a struct like a class. Then again, he could have some irrational idea of what a class is. Some people are like that.

One thing he suggested is an accesser function, he says it'll return the value of a private variable defined in the class.

That's a better design, but basically the same thing as Thantos' suggestion that you didn't like. You still have to call a function hundreds of times.

but I can't have the classes in an array, because I will have so many, they need names for me to keep track.

Why do they have to have names? What's wrong with a unique index that's so hard to remember for you?

So he suggested using a collection, or at least thats what he thinks they're called.

He was--hopefully--thinking of a map if the problem is assigning a name to each object.