VS Code - Only one cpp file from a project compiles - c++

Question

Okay so i have an error when am trying to run/compile the code.
Am guessing the problem is that my folder is not recognised as a project folder (i do not know how to solve that) and it compiles only one cpp file when it is needed to compile two of them.
error:
undefined reference to `Test2::fun()'
collect2.exe: error: ld returned 1 exit status
class.h
#include <iostream>
class Test2
{
public:
int a = 25;
void fun();
};
class.cpp
#include <iostream>
#include "class.h"
void Test2::fun()
{
std::cout << a;
}
main.cpp
#include <iostream>
#include "class.h"
int main()
{
Test2 e;
e.fun();
}
am not sure but that could be helpful to include my json files so... will include them
launch.json
{
// Use IntelliSense to learn about possible attributes.
// Hover to view descriptions of existing attributes.
// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
"version": "0.2.0",
"configurations": [
{
"name": "g++.exe - Build and debug active file",
"type": "cppdbg",
"request": "launch",
"program": "${fileDirname}\\${fileBasenameNoExtension}.exe",
"args": [],
"stopAtEntry": false,
"cwd": "${workspaceFolder}",
"environment": [],
"externalConsole": false,
"MIMode": "gdb",
"miDebuggerPath": "C:\\MinGW\\mingw64\\bin\\gdb.exe",
"setupCommands": [
{
"description": "Enable pretty-printing for gdb",
"text": "-enable-pretty-printing",
"ignoreFailures": true
}
],
"preLaunchTask": "C/C++: g++.exe build active file"
}
]
}
tasks.json
{
"tasks": [
{
"type": "cppbuild",
"label": "C/C++: g++.exe build active file",
"command": "C:\\MinGW\\mingw64\\bin\\g++.exe",
"args": [
"-g",
"${file}",
"-o",
"${fileDirname}\\${fileBasenameNoExtension}.exe"
],
"options": {
"cwd": "${workspaceFolder}"
},
"problemMatcher": [
"$gcc"
],
"group": {
"kind": "build",
"isDefault": true
},
"detail": "Task generated by Debugger."
}
],
"version": "2.0.0"
}
I am new into vs code, sorry if that is a pretty easy to solve problem but am trying to figure it out and i can not.
As i said am thinking that vs code does not recognise it as a project and runs only main.cpp cause the error looks like that when am trying to run the code.
I was trying to run same thing on codeblocks and visualstudio2019 and it was working corretly so there is a problem with my vs code set up i guess.
Thanks for help and have a goood day <3