Exercise 13      Name                                    Points __/35

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