C++ Essentials – Final Test

C++ Essentials – Final Test

  1. What is the output of the following snippet?

    #include <iostream>
using namespace std;
namespace OuterSpace
{
    int x = 1; 
    int y = 2;
}
namespace InnerSpace
{
    float x = 3.0;   
    float y = 4.0;
}
int main()
{  
    {using namespace InnerSpace;
         cout << x << " ";
    }{
         using namespace OuterSpace; using InnerSpace::y;
         cout << y;
    }
         return 0;
}
    • 3 4
    • 3 1
    • 3 2
    • Compilation error

  2. What is the output of the following snippet?

    #include <iostream>
using namespace std;
int main(int argc, const char *argv[])
{
   float B = 32;
   { char B = '1'; cout<<B;}
   { int B = 2; cout<<B;}
   cout<<B;
   return 0;
}
    • 1322
    • None of these 
    • 3212
    • 3122

  3. What is the output of the following snippet?

    #include <iostream>
using namespace std;
int main()
{
   int i = 0;
   for(; i < 5; i++);
   cout<<i;
   return 0;
}
    • 01234
    • 4
    • 012345
    • 5

  4. What is the output of the following snippet?

    #include <iostream>
#include <string>
using namespace std;
struct S
{
  char *p;
};
class C
{
   S s;
public:
   C() {s.p = new char; *s.p = 'A';}
   void p() {cout <<++(*s.p);}
};
int main()
{
   C *c = new C();
   c->p();
   return 0;
}
    • Compilation error
    • It prints garbage value 
    • B
    • A

  5. What is the output of the following snippet?

    #include <iostream>
#include <string>
using namespace std;
class One
{
   char value;
public:
   One() {value = 'A';}
   One(char v): value(v){}
   void set(char c) {this -> value =c;}
   void set(){this->value ='d';}
   char get() {return value;}
};
int main()
{
   One o1,*o2;
   o2 = new One('b');
   One *p;
   p = &o1;
   p->set();
   p = o2;
   p->set('c');
   cout<<o2->get() - o1.get();
   return 0;
}
    • -1
    • Compilation fails
    • 0
    • 1

  6. What is the output of the following snippet?

    #include <iostream>
using namespace std;
int doit(int a, float b)
{
   return a / b;
}
int main()
{
   float x = doit(1.5f, 21);
   cout<<x<<":"<<doit(1,1.f);
   return 0;
}
    • 0:1
    • 1:0
    • 1:1
    • 0:0

  7. What is the output of the following snippet?

    #include <iostream>
using namespace std;
int doit(int i, int j = 0)
{
   return (i * j);
}
int main()
{
   cout<<doit(doit(1,2));
   return 0;
}
    • 1
    • 0
    • 12
    • 112

  8. What is the output of the following snippet?

    #include <iostream>
using namespace std;
class Alpha {
public: char out(){ return 'A'; }
};
class Beta : public Alpha {
public: virtual char out(){ return 'B'; }
};
class Gamma : public Beta {
public: char out(){ return 'G'; }
};
int main()
{
   Alpha *a = new Alpha();
   Alpha *b = new Beta();
   Alpha *c = new Gamma();
   cout << (a->out()) << (b->out()) << (c->out());
   return 0;
}
    • AAA
    • BBB
    • ABG
    • GGG

  9. What is the output of the following snippet?

    #include <iostream>
using namespace std;
char max(char x, char y) {
   if(x > y)
      return y;
   else
      return x;
}
int main()
{
   char chr = max('a', 'z');
   cout << chr;
   return 0;
}
    • a
    • Compilation error
    • z
    • az

  10. What is the output of the following snippet?

    #include <iostream>
#include <string>
using namespace std;
class One {
public: float f;
   One(float f) { this -> f = f; }
};
class Two {
public: float f;
      Two (One o) { this -> f = o.f; }
       void foo() { cout << (int)f; }
};
int main()
{
   One o1(3.14);
   Two o2 = o1;
   o2.foo();
}
    • 3.14
    • 3
    • Compilation fails
    • 0

  11. What is the output of the following snippet?

    #include <iostream>
#include <string>
using namespace std;
class cmplx{
   double re, im;
public:
   cmplx() : re(1),im(1) {}
   cmplx(double r, double i) : re(r),im(i) {}
   cmplx operator+(cmplx &);
   void out() { cout << "(" << re << "," << im << ")"; }
};
cmplx cmplx::operator+ (cmplx &a){
   cmplx c (this->re + a.re, this->im + a.im);
   return c;
}
int main()
{
   cmplx x(1,2),y,z;
   z = x + y;
   z.out();
   return 0;
}
    • (2,3)
    • (2,2)
    • (3,3)
    • (3,2)

  12. What is the output of the following snippet?

    #include <iostream>
using namespace std;
int main() {
  int a = 0;
  if (++a == 1) {
     cout << (a >> 1);
  } else {
   cout << (a);
  }
   return 0;
}
    • 2
    • None of these
    • 0
    • 1

  13. What is the output of the following snippet?

    #include <iostream>
using namespace std;
int doit(int x)
{
   return x << 1;
}
int main()
{
   int i;
   i = doit(1) || doit(0);
   cout << i;
   return 0;
}
    • 1
    • 0
    • true
    • false

  14. Which code, inserted into the main function, generates the output 12?

    #include <iostream>
#include <string>
using namespace std;
string fun(string s1, string s2)
{
   return s1 + s2;
}
int main()
{
   string s="1", *t = &s;
   //insert code here
   return 0;
}
    • fun(*t,s);
    • fun(*t,"2");
    • fun("1", *t);
    • fun("1+2");

  15. What is the output of the following snippet?

    #include <iostream>
using namespace std;
int main()
{
   char *abc;

   abc = new char[26];
   for(int i = 0; i < 26; i++)
      abc[i] = 'a' + i;
   cout << *(abc + 2);
   return 0;
}
    • c
    • b
    • a
    • d

  16. What is the output of the program if the value of 1 is supplied as input?

    #include <iostream>
using namespace std;
class Uno {
public: char Char;
};
int main()
{
   int swtch;
   Uno u;
   u.Char = '5';
   cin >> swtch;
   try
  {
       switch (swtch)
       {
        case 3: throw 1;
        case 2: throw 3.f;
        case 1: throw u;
        }
   }
   catch (int e)
   { cout << e; }
   catch (Uno e)
   { cout << e.Char; }
   catch (...)
   { cout << "?"; }
   return 0;
}
    • 3
    • 1
    • 5
    • Compilation error

  17. What is the output of the following snippet?

    #include <iostream>
using namespace std;
int main()
{
   const char c = '!';
   const char *p;
   p = &c;
   *p = '?';
   cout<<*p;
   return 0;
}
    • !
    • Prints address of c
    • ?
    • Compilation fails

  18. What is the output of the following snippet?

    #include <iostream>
#include <cstdarg>
using namespace std;
int calculate(int &val, int arg)
{
   val *= arg;
   return arg;
}
int main()
{
   int i = 1;
   int j = calculate(i,2);
   cout << i << j;
   return 0;
}
    • 21
    • 11
    • 22
    • 12

  19. How many times will the program print HI!?

    #include <iostream>
using namespace std;
int X = 5;
int main()
{
   cout << "HI!";
   if(X-- > 0)
      main();
    return 0;
}
    • Two
    • One
    • Six
    • Five

  20. Which code, inserted into class C, generates the output by? Choose all correct answers.

    #include <iostream>
#include <string>
using namespace std;
class Uno {
protected: char y;
public:    char z;
};
   // insert code here
{
public:
void set(){
     y = 'a'; z = 'z';
}
void out() { cout << ++y << --z; }
};
int main(){
   Due b;
   b.set();
   b.out();
   return 0;
}
    • class Due : protected Uno
    • class Due : private Uno
    • class Due : public Uno
    • class Due

  21. What is the output of the following snippet?

    #include <iostream>
#include <string>
using namespace std;
class Class1 {
      char a;
protected:
      char b;
public:
      char c;
      Class1() { a='a'; b='b'; c='c'; }
};
class Class2: public Class1 {
      char d;
public: 
      void set() {
         c = 'e';
         d = 'd';
      }
};
int main(){
   Class2 a;
   a.set();
   cout << a.c << a.d;
   return 0;
}
    • cd
    • bd
    • ed
    • Compilation fails

  22. What is the output of the following snippet?

    #include <iostream>
using namespace std;
struct S {
   int a;
   char b;
   struct {
       float a;
       int b;
   } c;
};
int main (int argc, const char *argv[])
{
   S s = { 1, 2, 3, 4 };
   cout << s.c.a << s.c.b;
}
    • 14
    • 12
    • 34
    • 23

  23. What is the output of the following snippet?

    #include <iostream>
using namespace std;
int doit(int i, int j = 0)
{
   return (i * j);
}
int main()
{
   bool t[] = {false, true, false & true};
   string u[2] = {"false", "true"};
   bool *p;
   p = t + 2;
   cout << u[*p];
   return 0;
}
    • 1
    • false
    • true
    • 0

  24. What is the output of the following snippet?

    #include <iostream> 
using namespace std;
#define CALL(parm) {if(parm) cout<<parm++;}
int main()
{
   int i = 1;
   CALL(i);
   cout<<i;
   return 0;
}
    • 1
    • 12
    • 2
    • 11

  25. Which statement will you add in the following program to make it correct?

    #include <string>
int main()
{
   std::string s = "Here I am!";
   std::cout<<s;
   return 0;
}
    • #include
    • #include
    • #include
    • #include

  26. What is the output of the following snippet?

    #include <iostream> 
using namespace std;
int main()
{
   int x = -2, y;
   float f = 2.5, g;
   g = x;
   y = f;
   cout<<(int)g / y;
   return 0;
}
    • 0.8
    • -0.8
    • -1
    • 1

  27. What is the output of the following snippet?

    #include <iostream> 
#include <string>

using namespace std;
int main()
{
   string s1 = "top";
   string s2;
   s2.append(s1).append("down");
   cout<<s2;
   return 0;
}
    • downtop
    • down
    • top
    • topdown

  28. What is the output of the following snippet?

    #include <iostream> 
using namespace std;
class A
{ 
public: void out(){ cout << "A";}
};
class B: public A
{
public: void out(){ cout << "B";}
};
int main()
{
   A *a;
   a = new A();
   a -> out();
   a = new B();
   a -> out();
   return 0;
}
    • AB
    • BA
    • BB
    • AA

  29. What is the output of the following snippet?

    #include <iostream> 
using namespace std;
int main()
{
   const PI = 3.14;
   const PI2 = PI * PI;
   cout<<PI2;
   return 0;
}
    • 3
    • 9.8596
    • 3.14
    • Compilation fails 

  30. What is the output of the following snippet?

    #include <iostream> 
#include <string> 
using namespace std;
int boo(int v)
{
   v++;
   return ++v;
}
int main()
{
   float x = 3;
   x = boo(x);
   cout<<x;
   return 0;
}
    • 1
    • 5
    • -1
    • 3

  31. What happens if we use the operator new and the memory cannot be allocated?

    #include <iostream> 
#include <exception> 
using namespace std;
int main()
{
   long i = 2000000000;
   try 
   {
     char * test = new char[i];}
   catch (bad_alloc& e)
   { cout<<"1";}
   catch (exception& e)
   { cout<<"2";}
   catch (...)
   { cout<<"3";}
   return 0;
}
    • It prints 1
    • None of these 
    • It prints 2
    • It prints 3

  32. What is the output of the following snippet?

    #include <iostream> 
#include <string> 
using namespace std;
class Uno{
public: ~Uno() {cout << "X";}
};
void foo(Uno *d)
{
   Uno e;
   *d = e;
}

int main()
{
   Uno *u = new Uno;
   foo(u);
   delete u;
   return 0;
}
    • XX
    • XXX
    • X
    • XXXX

  33. What is the output of the following snippet?

    #include <iostream> 
#include <string> 
using namespace std;
const int size = 3;
class Uno{
public: int n;
     Uno(){n = 1;}
     Uno(int v) {n = v;}
};
class Due : public Uno{
public:
     int * arr;
     Due(): Uno(){
        arr = new int[n];
     }
     Due(int a): Uno(a){
        arr = new int[n];
     }
     ~Due() {delete arr;}
};
int main() {
     Due d(2);
     Due e;
     cout << d.n + e.n;
     return 0;
}
    • 4
    • 1
    • 2
    • 3

  34. What is the output of the following snippet?

    #include <iostream> 
using namespace std;
float doit(int a, int b)
{
    return a * b;
}
float doit(float a, float b)
{
    return a + b;
}
int main()
{
    cout<<doit(doit(1,2),doit(3.f,4.f));
    return 0;
}
    • 9
    • 21
    • 14
    • Compilation error

  35. What is the output of the following snippet?

    #include <iostream> 
using namespace std;
int main()
{
   int cnt = 10;
   do {
       cnt--;
       if (cnt % 3 == 2)
           break;
       cout << cnt;
    }
    while(cnt);
    return 0;
}
    • 987654321
    • 10987654321
    • 9
    • 109

  36. What is the output of the following snippet?

    #include <iostream> 
#include <string> 
using namespace std;
class Uno{
public: int Int;
};
class Due : public Uno{
public: Due() {Int = 2;}
      Due(int x) {Int = x == 0 ? 2 : x - 2;}
};
int main(){
      Due d,d2(0);
      cout << d.Int - d2.Int;
      return 0;
}
    • 1
    • 3
    • 0
    • 2

  37. What is the output of the following snippet?

    #include <iostream> 
using namespace std;
int main()
{
   int i = 2;
   float f = 1.4;
   char c = 'a';
   bool b = true;
   c += i + f + b;
   cout << c;
   return 0;
}
    • e
    • c
    • d
    • f

  38. What is the output of the following snippet?

    #include <iostream> 
using namespace std;
int main()
{
   int i = 10;
   float f = 2.5;
   cout << float(i) / int(f);
   return 0;
}
    • 0.5
    • 4
    • 1
    • 5

  39. What is the output of the following snippet?

    #include <iostream> 
#include <string> 
using namespace std;
struct Who
{
   string nick;
};
class She
{
       Who * who;
public:
       She(){
            who = new Who;
            who -> nick = "Jane";
       }
       string out(){
            return who -> nick;
       }
};
int main()
{
    She they[2];
    for(int i = 0; i < 2; i++)
        cout << they[i].out();
    return 0;
}
    • It prints nothing 
    • JaneJane
    • Jane
    • Runtime error

  40. Variable y in class Y, will be…

    class X {
private:   int x;
protected: int y;
public:    int z;
};
class Y: protected X{
};
    • none of these 
    • private
    • public 
    • protected

  41. What is the output of the following snippet?

    #include <iostream> 
using namespace std;
int main()
{
   int i = 8;
   do{
       i--;
       cout << i--;
    }
    while(i);
    return 0;
}
    • 76543210
    • 7531
    • 6543210
    • 6420

  42. What is the output of the following snippet?

    #include <iostream> 
#include <string> 
using namespace std;
class Uno{
      int val;
public: Uno(int x){val = x;}
        int out(){return val;}
        void operator++(int var){
             val += val;
        }
};
ostream &operator<<(ostream &o, Uno u)
{
    return o << u.out();
}
int main()
{
    Uno i(2);
    i++;
    cout << i;
    return 0;
}
    • 4
    • 3
    • 2
    • 1

  43. What is the output of the following snippet?

    #include <iostream> 
using namespace std;
bool compare(bool t, bool u)
{
     return t < u;
}
int main()
{
     cout << compare(true, false);
     return 0;
}
    • 0
    • true
    • 1
    • false

  44. What is the output of the following snippet?

    #include <iostream>
using namespace std;
class cmplx{
    double re, im;
public:
    cmplx(): re(0), im(0){}
    cmplx(double x) {re = im = x;}
    cmplx(double x, double y) {re = x; im = y;}
    void out(){cout<<"(" << re << "," << im << ")";}
};
int main()
{
    cmplx c(1,2), cc(c);
    cc.out();
    return 0;
}
    • (2,2)
    • (1,2)
    • (2,1)
    • (1,1)

  45. What is the output of the following snippet?

    #include <iostream> 
using namespace std;
class Sup{
public: virtual void out(){cout << "p";}
};
class Sub: public Sup{
public: virtual void out(){cout << "b";}
};
int main()
{
   Sub sub;
   Sup *sup;
   sup = &sub;
   sub.out();
   return 0;
}
    • bb
    • pb
    • bp
    • pp

  46. What is the output of the following snippet?

    #include <iostream> 
#include <string> 
using namespace std;
class Uno {
public: Uno() { cout << "X";}
};
Uno foo(Uno d)
{
    Uno e = d;
    return e;
}
int main()
{
    Uno u;
    foo(u);
    return 0;
}
    • X
    • XXX
    • XXXX
    • XX

  47. Which code, inserted into the function main, generates the output 03 ?

    #include <iostream> 
using namespace std;
class Uno 
{public: void foo(){cout << "0";}
         void bar(){cout << "1";}
};
class Due: public Uno
{public: void foo(){cout << "2";}
         void bar(){cout << "3";}
};
int main()
{
    Due d;
    //insert code here
    d.bar();
}
    • d->Due::foo();
    • d.Uno::foo();
    • d.Due::foo();
    • d->Uno::foo();

  48. What is the output of the following snippet?

    #include <iostream> 
using namespace std;
int k = -1;
class Class
{
public: char *adr;
       Class(){adr = new char[k];}
       ~Class() {delete[]adr;}
};
int fun(void)
{
    Class object;
    return 0.5f;
}
int main()
{
    fun();
    return 0;
}
    • 0.5
    • 0
    • 1
    • Runtime error

  49. Variable r in class C3, will be….

    #include <iostream> 
using namespace std;

class C1
{
public   int p;
private  int q;
protected  int r;
};
class C2: private C1{};
class C3: public C2{};
    • private
    • None of these
    • public
    • protected

  50. What is the output of the following snippet?

    #include <iostream> 
using namespace std;
class X1{
public: virtual void foo() = 0;
};
class X2: public X1{
public: virtual void foo(){cout << "X2";}
};
class X3: public X1{
public: virtual void foo(){cout <<"X3";}
};
int main()
{
    X1 *a = new X2(), *b = new X3();
    b->foo();
    b->foo();
    return 0;
}
    • X3X2
    • X3X3
    • X2X3
    • X2X2
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