why functions in a class are defined outside the class using scope operator

[vishnu123]

Hi all,

code below
class A
{
int a;
public:
int func(int x); //why the definition is given outside the class
}
int A::func(int x)
{
a=10;
cout << a <<endl;
}
but i studied that if we define inside class its default becomes an inline function. but another thing is inline is a request to compiler.if function has more number of statements its treated as normal fucntion itself.so why are we defining outside the class.

[MiiNiPaa]

why are we defining outside the class.

So we would not clutter the class by unneeded definitions. So we could separate implementation to another file making header lightweight