I've read that an `#include header.h` is a preprocessor (because of `#`), which means it gets processed before compilation.
Is that why my code can't run? Because I'm trying to make an if statement in main with my function from my header(that takes a parameter) and it won't work.

**Source.cpp**

```
#include <iostream>
#include "Header.h"
using namespace std;

int main(){
test(46);

if (test() > 30){
    cout << "great";
}
else{
    cout << "It needs to be higher";
}

    system("PAUSE");
    return 0;
}

```

**Header.h**

```
using namespace std;

    int test(int x){
        return x;
    }

```