Example

class MyClass
{
public:
int getA(){
return a;
}

private:
int a;
};

int global = 1;

int returnVar()
{
return global;
}

Solution

Use the :: operator to identify global variables.

class MyClass
{
public:
int getA(){
return MyClass::a;
}

private:
int a;
};

int global = 1;

int returnVar()
{
return ::global;
}