Reference no: EM133201574

1. Describe a situation when a history-sensitive variable in a subprogram is useful.

2. Consider the following JavaScript program:

var x, y, z;

function sub1() {

var a, y, z;

function sub2() {

var a, b, z;

. . .

}

. . .

}

function sub3()

{ var a, x, w;

. . .

}

Please list all the variables, along with the program units where they are declared, that are visible in the bodies of sub1, sub2, and sub3, assuming static scoping is used.