Problem Set 1- Solution

Problem 1:[15%]

Questions 1-3: Consider the following code:

        #include <iostream.h>
        extern int   x;                                                  // Statement a
        int main()
        {
                        int    a, b;                                       // Statement b
                        double d = 9;                                 // Statement c
                        a = 1;                                             // Statement d
                        b = 5;                                             // Statement e
                        cout << x+ a/b + d/10 << endl;
         }

2. Which line of the above code declares a variable without allocating memory for it?
     ->     a
 

3. Which lines of the above code are assignments?
     ->     d & e
 

4. According to the following statement:       const *int p;

b. the value of the integer that p points to cannot change

5. When the following logical test is true?

(  x>=y   &&  ! x   &&   x* y < 0  &&  y==0)

e. never

6. Which of the following cases of mixed expressions is/are correct (circle the correct one(s)), considering the following definition:

         double d; float f; int i; char c;

  c.   ’f’ - ’d’                 is an int

7. What is the result of the statement following the definitions given below?

                          char c='b';
                          char *pc=&c;
                          char *&rc=pc ;
                           (*rc)++;

 c. it increases *rc
 

           double x= 0.5, y=4.9;
          double *px, *py, &rx=x;

 
a. px =&x;  double &rx = *px ;
d. px = px = rx;
e. px = py = *x;
 

        void *pp = &x;
        double *px=&x;
        double **ppx=&px;

 a. **ppx
 b. *(static_cast <double*>(pp))
 d. *(*(&px))
 e. *( (double*)pp)

a.  ’z’ - ’t’
b.  13 % 7
e.   55 % 7

  int x = (7>6 ? 1+8 : 8)

 e. 9

 a. void func(int x);
 e.  void func(int);

               float f;
               printFun(2.0*f);

b. void printFun(double)
 

int fib(int num)   // Fibonacci value of a number
{
   switch(num)
    {
      case 0:
               return(0);
               break;
      case 1:
               return(1);
               break;
      default:
               return(fib(num - 1) + fib(num - 2));
               break;
   }
}

d. 5
 

e. No value is returned

  Problem 2:[5%]

bool b;
char c;
int i;
float f;
double d;
 

  1.     77 + c + i + 1L                                      long int
  2.     6.55f  + f  /  1.5  - 9 / 8                         double
  3.    ’z’  -  ’z’                                                 int
  4.     b + c                                                      int
  5.     ’t’ - ’a’ + c                                             int
  6.     77.8f + 4 * 0.5f  +45L                            float
  7.     42L + (int) d  +  94.3f  + int(4.9)           float
  8.     0.0 + f  +c                                              double
  9.     5.28L * d * 3  + 4.5                                long double
10.     1.5f / d * f +  6.9 * 4L                            double
 
 

  Problem 3:[10%]

 
// Problem Set#1 - Problem#3 [ps1_3.h]

#ifndef PS1_3_H
#define PS1_3_H

#include <iostream.h>
#include <stdlib.h>
#include <string.h>
 

class Material
{
 public:
  char name[20];
  double modulusElasticity;
  double ratioPoisson;
  Material();
  void print(void);
};

#endif

   // Problem Set#1 - Problem#3 [ps1_3.C]

#include "sol1_3.h"

Material::Material()
{
  strcpy(name,"None");
  modulusElasticity = 0.0;
  this -> ratioPoisson = 0.0;
}

void Material:: print(void)
{
  cout << "\n Material: " << name
       << "\n Modulus of elasticity = " << modulusElasticity
       << "\n Poisson ratio = " << ratioPoisson << endl;
}

char name[40] = "Foundation of Software Engineering";

int main()
{
  char name[30] = "Problem 3";
  Material m;

  cout << "\n Local name : "
       << name ;
  cout << "\n Global name : "
       << ::name;
  cout << "\n Object name : "
       << m.name;

  cout << "\n\n Object: " ;
  m.print();

  cout << "\n Exiting properly\n" << endl;
  return EXIT_SUCCESS;
}
 

Problem 4:[10%]

1.

   int x;
   int *y;
   int **z;

   x = 0;
   y = &x;
   z = &y;

    x++;
    (*y)++;
    (**z) = 10;
    cout <<    "x is " << x <<
    " *y is " << *y <<
    " **z is " << **z << endl;

x is 10 *y is 10 **z is 10
 

2.

   void increment (int &a, int b, int *c)
   {
        a++;
        b++;
        (*c)++;
        cout << "a is " << a << " b is " << b << " c is " << *c << endl;
   }

    int main()
    {
       int x=0, y=0, z=0;
       increment (x,y,&z);
     cout << "x is " << x << " y is " << y << " z is " << z << endl;
   }

a is 1 b is 1 c is 1
x is 1 y is 0 z is 1
 

3.

void swap(int *a, int *b)
{
  int *tmp;

  tmp = a;
  a = b;
  b = tmp;
}

int main (){
  int x[] = {1, 1, 1};
  int y[] = {2, 2, 2};
  swap (x,y);
  cout << " x[0] = " << x[0] << "  y[0] = " << y[0] << endl ;
}

x[0] = 1  y[0] = 2
 

4.

double scale(double x, double s=1, double offset=0);

double scale(double x, double s, double offset)
{
    return s*x + offset;
}

int main()
{
    double value=20;

   double test1 = scale(value);
   double test2 = scale(value,2.54);
   double test3 = scale(value, 9.0/5.0, 32.0);

   cout << "  test1=" << test1
          << "  test2=" << test2
          << "  test3=" << test3 << endl;
   return 0;
}

  test1=20  test2=50.8  test3=68
 

5.

     void func2 (int& a, int& b)
     {
         int tmp = a;
         a = b;
         b = tmp;
     }
 

     void func1 (int a, int b)
     {
         a /= 2;
         b *= 2;

         cout << "Before func2" << endl;
         cout << " a = " << a << " b = " << b << endl;

         func2 (a, b);

         cout << "After func2" << endl;
         cout << " a = " << a << " b = " << b << endl;
     }
 

    int main()
     {
         int a = 10;
         int b = 20;

         cout << "At the beginning" << endl;
         cout << " a = " << a << " b = " << b << endl;

         func1 (a, b);
         func2 (a, b);

         cout << "At the end" << endl;
         cout << " a = " << a << " b = " << b << endl;
     }

At the beginning
a = 10 b = 20
Before func2
a = 5 b = 40
After func2
a = 40 b = 5
At the end
a = 20 b = 10
 

Problem 5:[40%]

// Problem Set#1 - Problem#5 [sol1_5.h]
 

#ifndef SOL1_5_H
#define SOL1_5_H

#include <iostream.h>
#include <stdlib.h>
#include <string.h>

int main();

int getHeight();

void checkHeight(int n);

void drawHourglass(int n);
 

#endif

// Problem Set#1 - Problem#5 [ps1_5.C]

#include "sol1_5.h"

int main()
{
  int n;          // Height of figure

  n =  getHeight();
  checkHeight(n);
  drawHourglass(n);

}

int getHeight()
{
  int n;
  cout << "Enter height of figure, n : ";
  cin >> n;
  cout << endl;
  return n;
}

void checkHeight(int n)
{
  if (n % 2 == 0 || n < 3)
    {
      cout << "Bad value for n!! exiting..." << endl << endl;
      exit(-1);
    }
}
 

void drawHourglass(int n)
{
  int i, j;

  for (i=0; i<n; i++)  // Print top row of '*'s
    cout << '*';

  cout << endl;

  for ( j = n/2 - 2; j >= 0; j-- )  // Print upper rows
    {
      for ( i = 0; i < n/2-j-1; i++ )  // Move to position of first '*'
        cout << ' ';

      cout << '*';  // Print first '\'

      for ( i = 0; i < 2*j+1; i++)  // Print spaces
        cout << ' ';

      cout << '*' << endl;  // Print second '*' and end line
    }
  for ( i = 0; i < n/2; i++ ) // Print center row
    cout << ' ';

  cout << '*' << endl;

  for ( j = 1; j < n/2; j++ )  // Print lower rows
    {
      for ( i = 0; i < n/2-j ; i++ )  // Move to position of first '*'
        cout << ' ';

      cout << '*';  // Print first '|'

      for ( i = 0; i < 2*j -1; i++)  // Print spaces
        cout << ' ';

      cout << '*' << endl;  // Print second '*' and end line
    }

  for (i=1; i<=n; i++)  // Print bottom row of '*'s
    cout << '*';

  cout << endl << endl;

}

Problem 6:[20%]

#include  <iostream.h>  // Problem Set#1 - Problem#6 solution  [sol1_6.h]
#include  <stdlib.h>

class Complex
{
private:
  double real;
  double imaginary;

public:
  Complex(double real=0, double imaginary=0)
  {
    cout << "\n In   Complex(" << real
         <<  "," << imaginary << ") constructor" << endl;
    this -> real = real ;
    this -> imaginary = imaginary ;
  }

  double get_real(void);
  double get_imaginary(void);
  void set_real(double);
  void set_imaginary(double);

};

#include  "sol1_6.h"  // Problem Set#1 - Problem#6 solution  [sol1_6.C]
 

double Complex::get_real(void)
{
  return real;
}

double Complex::get_imaginary(void)
{
  return imaginary;
}

void Complex::set_real(double real)
{
  this -> real = real ;
}

void Complex::set_imaginary(double im)
{
  imaginary = im;
}

int main ( )
{
  Complex c1;

  cout << "\n\n c1 = " <<  c1.get_real()
       << " + " << c1.get_imaginary() << "i " << endl ;

  Complex c2(7.25,-8.5);
  cout << "\n\n c2 = " <<  c2.get_real()
       << " + " << c2.get_imaginary() << "i " << endl ;

  c1.set_real(1.7);
  c1.set_imaginary(-6.7);
  cout << "\n\n c1 = " <<  c1.get_real()
       << " + " << c1.get_imaginary() << "i " << endl << endl;

  return  EXIT_SUCCESS ;

}
 
 

 In   Complex(0,0) constructor
 

 c1 = 0 + 0i

 In   Complex(7.25,-8.5) constructor
 

 c2 = 7.25 + -8.5i
 

 c1 = 1.7 + -6.7i

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