Below are questions that test your understanding of C++ parameter passing.
All are taken from Test 1 in CSE 17 in the given semester.
See www.lehigh.edu/~ejk0/examfile.html for the answers.

Spring 1998
 3.  (15 pts)  Given the function and variable declarations below, state
         what output is generated by the code below the dashed line.

         void a(int & x, int y,int & z)
          { x=y+z;
            y=y+z;
            z=z+2;
            cout << x << " " << y << " " << z<<endl; }
     -----------------------------------------------------------
      int x=1,y=2,z=3;
      a(x,y,z);
      cout << x << " " << y << " " << z << endl;
      x=1; y=2; z=3;
      a(z,y,x);
      cout << x << " " << y << " " << z << endl;
      x=1; y=2; z=3;
      a(x,x,x);

Fall 1998
  6.  (15 pts) This question assumes the function enigma is defined as
    follows:
             void enigma(int a, int &b, int &c) {
                a=a+b;
                b=b+2;
                c=c+2;
                cout<<a<<" "<<b<<" "<<c<<endl;
             }
    What is the output of each of the code fragments:

       (a) int x=1,y=2,z=3;
           enigma(x,y,z);                         
           cout<<x<<" "<<z<<endl;                  
       (b) int a=1,b=2,c=3;
           enigma(c,b,a);                         
           cout<<a<<" "<<c;                       
       (c) int a=1,z=2;
           enigma(a,a,a);                         
           cout<<a<<" "<<z;    

Spring 1999                    
3.  (14  pts) Suppose we have the following variable declarations
    and function definition:
        void x(int a, int &b, int c, int&d){
          a=a+1;
          b=b*a;
          c=c+2;
          d=d*c;
        }
      int a, b, c, d;

    State the output when the following statements are executed;
       a=1; b=2; c=3; d=4;
       x(a,b,c,d);
       cout<<a<<" "<<b<<"  "<<c<<" "<<d<<endl;     
       a=1; b=2; c=3; d=4;
       x(b,c,d,a);
       cout<<a<<" "<<b<<"  "<<c<<" "<<d<<endl;    
       a=1; b=2; c=3; d=4;
       x(a,b,b,a);
       cout<<a<<" "<<b<<endl;                     
       a=1; b=2; c=3; d=4;
       x(b,a,b,a);
       cout<<a<<" "<<b<<"  "<<c<<" "<<d<<endl;   
Summer 1999
 1.  (10 pts)Given the function definitions below, state what output is
          generated by the code below the dashed line.

          void b(int & x, int &y)
           {y++;
            x+=y;
            cout <<x<<" "<<y<<" ";
           }

          void a(int & x, int& y,int  z)
          { x=y+z;
            y=y+z;
            b(x,z);
            cout << x << " " << y << " " << z<<endl; }

     -----------------------------------------------------------
      int u=1,v=2,w=3;                              
      a(u,v,w);                                     
      cout << u << " " << v << " " << w << endl;   
      w=3;
      b(w,w);

Fall 1999
 2.  (15 pts)Given the function definition below, state what output is
          generated by the code below the dashed line.
          void q(int & x, int& y,int  z)
          { x=x+2;
            y=y+3;
            z=z+1;
            x=z+2;
            cout << x << " " << y << " " << z<<endl; }
     -----------------------------------------------------------
      int x,a,y;
      x=1; a=2; y=3;
      q(x,a,y);                                        
      cout << x << " " << a << " " << y << endl;        
      x=1; a=2; y=3;
      q(x,a,x);                                         
      cout << x << " " << a << " " << y << endl;       
      x=1; a=2; y=3;
      q(x,x,x);                                         

Fall 2000
3. (12 pts) State the output of the following main program.
  void func(int a, int &b, int &c, int *d, int *&e){
    d=&c;
    e=&b;
    a++;
    b+=a;
    c+=b;
    cout<<a<<" "<<b<<" "<<c<<endl;
  }
  void main(){
    int x,y,z, *tPt,*vPt;
    x=1;
    y=5;
    z=10;
    tPt=&y;
    vPt=&x;
    func(x,y,z,tPt,vPt);                  2 7 17
    cout<<x<<" "<<y<<" "<<z<<endl;        1 7 17
    x=10; y=20;
    func(x,x,x,tPt,vPt);                  11 42 42
    cout<<x<<" "<<*tPt<<" "<<*vPt<<endl;  42 42 42

Fall 2001
3. (18 pts) State the output of the following main program.

    bool v(int &a,int &b,int c)
     {a++;
      b=b+a;
      return a+b>3*c;
     }
    void out(bool t,int a, int b)
    {if(t)
      cout<<a<<"  "<<b<<endl;
     else
      cout<<b<<"  "<<a<<endl;
    }
    int main()
     { int a,b;
       bool t;
       a=2;  b=3;
       t=v(a,b,5)
       out(t, a, b);                 
       a=2;   b=3;
       t=v(b,a,8) && v(b,a,8);     
       out(t, a, b);
       a=2;
       t=v(a,a,3*a);                 
       out(t, a, a);

     }
Fall 2007
4. Below each output statement (cout<<...) write down the output that
occurs.
#include <iostream>
using namespace std;

void one(int x, int &y, int &z);
void two(int *x, int *&y, int v[]);

int main(){
  int xx,yy,zz;
  xx=1;
  yy=2;
  zz=3;
  one(zz,yy,xx);
  cout<<xx<<" "<<yy<<" "<<zz<<endl;
 //------------------------------------- 1
  xx=1;
  one(xx,xx,xx);
  cout<<xx<<endl;
 //------------------------------------- 2
  int *x, *y, v[]={1,2,3};
  x=v;
  y=&v[1];
  two(x,y,v);
  cout<<*x<<" "<<*y<<" "<<v[0]<<" "<<v[1]<<" "<<v[2]<<endl;
 //------------------------------------- 3
    }

 void one(int x, int &y, int &z){
  int temp;
  temp=x;
  x=y;
  y=temp;
  x+=2;
  y+=x;
  z=x+y;
  }

 void two(int *x, int *&y, int v[]){
   y=&v[2];
   *x=7;
   x=y;
   *x=8;
 }
 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
   //---- 1:      11  7  3
   //---- 2:      7
   //-----3:      7 8 7 2 8
 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Spring 2007
2.  For each question below, assume that the same main() given here:
       #include <iostream>
       using namespace std;
       int main(){
	int a,*b,c;
	a=10;
	b=&c;
	c=20;
	x(a,a,b);
	cout<<a<<" "<<*b<<" "<<c<<endl;
       }

  a) State the output of the above program if x is defined by
       void x(int y, int z, int *t) //>>>>>>>>>>>>>>>>>> 10 42 42
       { *t=42;
	 y+=4;
	 t=&z;
	 z+=y+3;
       }

  b) State the output of the above program if x is defined by
       void x(int &y, int z, int *t) //>>>>>>>>>>>>>>>>> 14 42 42
       { *t=42;
	 y+=4;
	 t=&z;
	 z+=y+3;
       }

  c) State the output of the above program if x is defined by
       void x(int &y, int& z, int *t) //>>>>>>>>>>>>>>>> 31 42 42
       { *t=42;
	 y+=4;
	 t=&z;
	 z+=y+3;
       }

  d) State the output of the above program if x is defined by
       void x(int &y, int& z, int *&t) //>>>>>>>>>>>>>>> 31 31 42
       { *t=42;
	 y+=4;
	 t=&z;
	 z+=y+3;
       }