[Solved] CSE 461: Programming Languages ConceptsHomework 2:

1. (8 points) Consider the C program given below. You will be asked to determine which variables are visible in a number of different situations. In each case, identify each variable by its name and the line number of its declaration.
   • int h, i;
   • void B(int w) {
   • int j, k;
   • i = 2*w;
   • w = w+1;
   • }
   • void A (int x, int y) {
   • float i, j;
   • B(h);
   • i = 3;
   • }
   • void main() {
   • int a, b;
   • h = 5; a = 3; b = 2;
   • A(a, b);
   • B(h);
   • }
   • C uses static scoping. Say which identifiers (including variablesand function names) are visible in the bodies of each of the functions: main, A, B.

1

• If C used dynamic scoping and the calling sequence is main callsB. Say which identifiers would be visible in B.
• If C used dynamic scoping and the calling sequence is main callsA. Say which identifiers would be visible in A.
• If C used dynamic scoping and the calling sequence is main callsA; A calls B. Say which identifiers would be visible in B.

2. (3 points) Find some online material to learn C++s namespace mechanism. Explain briefly how it works and its benefits.
3. (3 points) During the execution of a Java program, can a variable be visible but not allocated? Can a variable be allocated but not visible? Explain your answers.