#Blender - Prototype to capture the output of a C++ program supplied by an add-on

__init__.py

# ##### BEGIN GPL LICENSE BLOCK #####
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License
#  as published by the Free Software Foundation; either version 2
#  of the License, or (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software Foundation,
#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
# ##### END GPL LICENSE BLOCK #####


bl_info = {
    "name": "Add-on Template",
    "description": "",
    "author": "p2or",
    "version": (0, 4),
    "blender": (3, 0, 0),
    "location": "3D View > Tools",
    "warning": "", # used for warning icon and text in addons panel
    "doc_url": "https://blender.stackexchange.com/a/57332",
    "tracker_url": "https://gist.github.com/p2or/2947b1aa89141caae182526a8fc2bc5a",
    "support": "COMMUNITY",
    "category": "Development"
}

import bpy
from pathlib import Path


# ------------------------------------------------------------------------
#    Operators
# ------------------------------------------------------------------------

class WM_OT_HelloWorld(bpy.types.Operator):
    bl_label = "Report Values"
    bl_idname = "wm.hello_world" 
    
    def execute(self, context):

        from subprocess import PIPE, Popen
        out, err = Popen(app, stdout=PIPE).communicate()

        x_values, y_values, z_values = [],[],[]
        out = out.splitlines()

        for line in out:
            line = line.strip()
            columns = line.split()
            x_values.append(float(columns[0]))
            y_values.append(float(columns[1]))
            z_values.append(float(columns[2]))

        print (z_values)
        self.report({'INFO'}, ", ".join(map(str, z_values)))
        return {'FINISHED'}


# ------------------------------------------------------------------------
#    Panel in Object Mode
# ------------------------------------------------------------------------

class OBJECT_PT_CustomPanel(bpy.types.Panel):
    bl_label = "My Panel"
    bl_idname = "OBJECT_PT_custom_panel"
    bl_space_type = "VIEW_3D"   
    bl_region_type = "UI"
    bl_category = "Tools"
    bl_context = "objectmode"   

    @classmethod
    def poll(self,context):
        return context.object is not None

    def draw(self, context):
        layout = self.layout
        layout.use_property_split = True
        layout.use_property_decorate = False  # No animation.

        layout.label(text="Path to executable: " + str(app))
        layout.operator("wm.hello_world")
        layout.separator()


# ------------------------------------------------------------------------
#    Registration
# ------------------------------------------------------------------------

# Path to the app
app = Path(__file__).parent / "random-numbers"

classes = (
    WM_OT_HelloWorld,
    OBJECT_PT_CustomPanel,
)

def register():
    from bpy.utils import register_class
    for cls in classes:
        register_class(cls)
    
    import stat
    app.chmod(app.stat().st_mode | stat.S_IEXEC)
    #os.chmod(str(app), st.st_mode | stat.S_IEXEC)

def unregister():
    from bpy.utils import unregister_class
    for cls in reversed(classes):
        unregister_class(cls)

random-numbers.cpp

#include <iostream>     // std::cout
#include <vector>       // std::vector
#include <ctime>        // std::time
#include <cstdlib>      // std::rand, std::srand

int main () {

  std::vector<float> z(10);
  float x = 0.171; 
  float y = 0.324;

  // iteration to store random numbers
  std::srand (static_cast <unsigned> (std::time(0)));
  for (std::vector<float>::iterator i = z.begin(); i != z.end(); i++){
    *i = static_cast <float> (rand()) / static_cast <float> (RAND_MAX);
  }

  // iteration to print x y z values
  for (std::vector<float>::iterator i = z.begin(); i != z.end(); i++){
    std::cout << (*i * x) << " " << (*i * y) << " " << *i << "\n";
  }

  return 0;
}