Exercise 13      Name                                    Points __/35

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1. Compute wp for the following:
   1. (1) {x > -10} y := x + 13;              {y > 3} 
       
   2. (1) {y < x - 2} x := x - y + 2;         {x > 4}
       
   3. (2) {x < 2} y := x + 7;                  {y < 9}
           {y < 9} x := y - 5;                   {x < 4}
       
   4. (2) {y > 13}
           if (x<5) then
                  {y > -2} y := y + 7          {y > 5}
           else {y > 13} y := y - 8           {y > 5}
       
   5. (2) {y > 13 && x > -2}
           if (x<5) then
                  {x > -2} y := x + 7          {y > 5}
           else {y > 13} y := y - 8           {y > 5}
       
   6. (2) {y > 13 && x > y-2}
           if (x<5) then
                  {x > y-2} y := x + 7 - y    {y > 5}
           else {y > 13}  y := y - 8          {y > 5}
       
   7. (3) {y > 13 }
           if (x<5) then
           {y > 6}  x := y + 3                  {x > 9}  
           {x > 9}  y := x - 4                   {y > 5}
           else          
           {y > 13} y := y - 8                  {y > 5}

2. (10) Scoping

1. Give the static scoping diagram.

2. What is the result with static scoping?

3. Give the dynamic scoping diagram.

4. What is the result with dynamic scope?

int z = 2; int add ( int f(int), int z) {  return f ( z ); } int p(int x) { return x+z; } void main() { cout << add( p, 3); }

3. (12 pts) What is the output of the following for:

1. x is passed by value and y is passed by value;
2. x is passed by value and y is passed by name;
3. x is passed by name and y is passed by value; and
4. x is passed by name and y is passed by name?

#include <iostream.h>

int I = 0;
int A[3] = { 7, 11, 13 };

void P(int x, int y) {
        y = 1;
        cout << x << "\t";
        I = 2;
        cout << x << "\t";
        I = 2;
        cout << x << "\t";
        cout << y << "\n";
}

void main() {
        P( A[I],  I );
        P( I     , A[I] );
 }