what is difference between deep binding and shallow binding? Explain with this code.

Question

int x=5;
void f()
{
    x = x+50;
}

void g(h())
{
    int x=10;
    h();
    print(x);
}

void main()
{
    g(f());
    print(x);
}

1) what is output if code uses deep binding?

2)what is the output if code uses shallow binding?

Answer 1

Deep/shallow binding makes sense only when a procedure can be passed as an argument to a function.

• Deep binding binds the environment at the time a procedure is passed as an argument.
• Shallow binding binds the environment at the time a procedure is actually called. 

1. Deep binding.

f() gets the environment of main, since f() is passed as an argument in main. At the time of passing, x in main (the global x) is 5. So, f changes the global x to 55, and g prints the local x as 10.

2. Shallow binding.

f() gets the environment of g at the time it is called. So, f changes the x in g to 10+50 = 60, and g prints the value 60.

Comments

@Arjun thank u sir

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sir,as you said, is  it mean f() is calculated when it passed as argeument in g() before calling g()  ?can  you explain brief?

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No. It is not about being called.

{ int x = 2; { int x = 3; { int y = x; }}}

Now, value of y is ?

In most languages it is 3 because that is the most closely matching declaration for x. Similarly, when we call a function (not for languages like C where we can't pass a function as parameter), the variables also gets binded. i.e., inside the function we can use variables from the place the function is called. Now, deep and shallow bindings are two ways in which such variable bindings take place. Now, you can read the above answer.

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what would be the value of x printed in main in case of shallow binding? 5 or 60 ? ..is it anyway similar to static and dynamic binding?