DHANALAKSHMI COLLEGE OF ENGINEERING, CHENNAI

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1 DHANALAKSHMI COLLEGE OF ENGINEERING, CHENNAI Department of Computer Science and Engineering CS6202 PROGRAMMING DATA STRUCTURES II Anna University 2 & 16 Mark Questions & Answers Year / Semester: II / III Regulation: 2013 Academic year:

2 UNIT III Part A 1. Distinguish the term template class and class template. [M/J 16] A class that has generic definition or a class with parameters which is not instantiated until the information is provided by the client. It is referred to a jargon for plain templates. Example: someclasssc; // someclass is an ordinary(non-template) class someclass<int.sc; //someclass<int>is a template class The individual construction of a class is specified by a class template which is almost similar the way how individual objects are constructed by using a class. It is referred to a jargon for plain classes. Example: template<typename t> class someclass ;//this is a template class template<typename t> intsome_function(t&).. //this is a function template 2. List out the types of containers. [M/J 16] Two basic types of containers: Sequences o User controls the order of elements. o vector, list, deque

3 Associative containers o The container controls the position of elements within it. o Elements can be accessed using a key. o set, multiset, map, multimap 3. What is an abstract class? [N/D-16] An abstract class is a class that is designed to be specifically used as a base class. An abstract class contains at least one pure virtual function. You declare a pure virtual function by using a pure specifier (= 0) in the declaration of a virtual member function in the class declaration. The following is an example of an abstract class: class AB public: virtual void f() = 0; ; Function AB::f is a pure virtual function. 4. What is a function adaptor? [N/D-16] A function adaptor is an instance of a class that adapts a namespace-scope or member function so that the function can be used as a function object. A function adaptor may also be used to alter the behavior of a function or function object. Each function adaptor defined by the C++ Standard Library provides a constructor that takes a namespace-scope or member function. The adaptor also defines a function call operator that forwards its call to that associated global or member function. 5. Give the various file stream classes needed for file manipulation. [ M/J 15] filebuf fstreambase ifstream ofstream fstream 6. Is Abstract base class, used to create objects? Justify your answer in brief. [ M/J 15] No. simply abstract class contains abstract methods(means the functions which are without the body) and we cannot give functionality to the abstract methods. And if we try to give functionality to the abstract methods then there will be no difference between abstract class and virtual class. So lastly if we create an object Of an abstrast class then there is no fun to call the

4 useless functions or abstract methods as they are without the functionality..sothats why any language doesnt allow us to create an object of an abstract class. 7. Compare overloaded functions versus function templates. [N/D-15] A function template works in a similar to a normal function, with one key difference. A single function template can work with different data types at once but, a single normal function can only work with one set of data types. Normally, if you need to perform identical operations on two or more types of data, you use function overloading to create two functions with the required function declaration. the sum function template defined above can be called with: x = sum<int>(10,20); The function sum<int> is just one of the possible instantiations of function template sum. In this case, by using int as template argument in the call, the compiler automatically instantiates a version of sum where each occurrence of SomeType is replaced by int, as if it was defined as: int sum (int a, int b) returna+b; 8. Giveanexampleonfunctiontemplate. [N/D-14] #include<iostream> usingnamespacestd; // template function template<class T> T Large(T n1, T n2) return(n1 > n2)?n1 : n2; int main() int i1, i2; float f1, f2; char c1, c2;

5 cout<<"enter two integers:\n"; cin>> i1 >> i2; cout<<large(i1, i2)<<" is larger."<<endl; cout<<"\nenter two floating-point numbers:\n"; cin>> f1 >> f2; cout<<large(f1, f2)<<" is larger."<<endl; cout<<"\nenter two characters:\n"; cin>> c1 >> c2; cout<<large(c1, c2)<<" has larger ASCII value."; return0; 9. What isthe significanceofiterators? [N/D-14] Iterators are used to step through the elements of collections of objects. These collections may be containers or subsets of containers. Functions in iterartors advance-it advances the iterator it by n element positions. distance-it returns distance between iterators. begin-it is used to begin an iterator. end-it is used to end an iterator. prev-it is used to get iterator to previous element. next-it is used to get iterator to next element.

6 Part - B 1. Write a class template to represent a queue of any possible data type(8) [M/J 16 ] #include<iostream> #include<string> using namespace std; template<typename T> voidprint_mydata(t output) cout<< "Output value: " << output <<endl; int main() int i=5; double d=5.5; string s("hello World"); bool b=true; print_mydata(i); // T is int print_mydata(d); // T is double print_mydata(s); // T is string print_mydata(b); // T is bool return 0; As we said before, templates are expanded by the compiler in as many definitions as the function calls of the different types used. Data-types are represented by a common name, which is replaced by different actual data-type by the compiler, during compilation. Data-types used by the compiler, are evaluated using the function calls made by the programmer in the program. In the example above, the compiler will create four definitions of the print_mydata function as follows (as per the function call): voidprint_mydata(int output) cout<< "The value is: " << output <<endl;

7 voidprint_mydata(double output) cout<< "The value is: " << output <<endl; voidprint_mydata(string output) cout<< "The value is: " << output <<endl; voidprint_mydata(bool output) cout<< "The value is: " << output <<endl; Note: As you can see, only the type of the parameter output is changing. For function templates, there are two options to specify the template parameters. template<typename T> voidmy_function() int main() my_function<int>(2); my_function<double>(2.1); Or we could do this (like we did in the first example print_mydata): template<typename T> voidmy_function(t value) int main()

8 //T = int my_function(2); //T = double my_function(2.1); The following points you could also do with template functions: a) One template function can use more than one generic type. We could say: template(typename T, typename T1) b) We can use specific data-types along with the generic types in the function templates. So for example: template<typename T> voidprint_mydata(t output, int a) So if we call print_mydata from main it should be something like this: int i=5; double d=5.5; print_mydata(i, 5); print_mydata(d, 5); Note: The second parameter should always be an integer. c) We can overload the function templates (by creating another overloaded template function of the same name).

9 2. Illustrate about how exceptions are handled using multiple catch handlers.(8) [M/J 16 ] An exception is a problem that arises during the execution of a program. A C++ exception is a response to an exceptional circumstance that arises while a program is running, such as an attempt to divide by zero. Exceptions provide a way to transfer control from one part of a program to another. C++ exception handling is built upon three keywords: try, catch, and throw. throw: A program throws an exception when a problem shows up. This is done using a throw keyword. catch: A program catches an exception with an exception handler at the place in a program where you want to handle the problem. The catch keyword indicates the catching of an exception. try: A try block identifies a block of code for which particular exceptions will be activated. It's followed by one or more catch blocks. Assuming a block will raise an exception, a method catches an exception using a combination of the try and catch keywords. A try/catch block is placed around the code that might generate an exception. Code within a try/catch block is referred to as protected code, and the syntax for using try/catch looks like the following: try // protected code catch( ExceptionName e1 ) // catch block catch( ExceptionName e2 ) // catch block catch( ExceptionNameeN ) // catch block You can list down multiple catch statements to catch different type of exceptions in case your try block raises more than one exception in different situations. #include<iostream.h> #include<conio.h>

10 void test(int x) try if(x>0) throw x; else throw 'x'; catch(int x) cout<<"catch a integer and that integer is:"<<x; catch(char x) cout<<"catch a character and that character is:"<<x; void main() clrscr(); cout<<"testing multiple catches\n:"; test(10); test(0); getch(); Output: Testing multiple catches Catch a integer and that integer is: 10 Catch a character and that character is: x

11 3. Explain the components of STL.(8) [M/J 16] (13) [N/D-16] (6) [M/J 15](8)[N/D-15] The C++ STL (Standard Template Library) is a powerful set of C++ template classes to provides general-purpose templatized classes and functions that implement many popular and commonly used algorithms and data structures like vectors, lists, queues, and stacks. At the core of the C++ Standard Template Library are following three well-structured components: Component Containers Algorithms Iterators Description Containers are used to manage collections of objects of a certain kind. There are several different types of containers like deque, list, vector, map etc. Algorithms act on containers. They provide the means by which you will perform initialization, sorting, searching, and transforming of the contents of containers. Iterators are used to step through the elements of collections of objects. These collections may be containers or subsets of containers. We will discuss about all the three C++ STL components in next chapter while discussing C++ Standard Library. For now, keep in mind that all the three components have a rich set of predefined functions which help us in doing complicated tasks in very easy fashion. Let us take the following program demonstrates the vector container (a C++ Standard Template) which is similar to an array with an exception that it automatically handles its own storage requirements in case it grows: #include<iostream> #include<vector> usingnamespacestd; int main() // create a vector to store int vector<int>vec; int i; // display the original size of vec cout<<"vector size = "<<vec.size()<<endl;

12 // push 5 values into the vector for(i =0; i <5; i++) vec.push_back(i); // display extended size of vec cout<<"extended vector size = "<<vec.size()<<endl; // access 5 values from the vector for(i =0; i <5; i++) cout<<"value of vec ["<< i <<"] = "<<vec[i]<<endl; // use iterator to access the values vector<int>::iterator v =vec.begin(); while( v!=vec.end()) cout<<"value of v = "<<*v <<endl; v++; return0; When the above code is compiled and executed, it produces the following result: vector size = 0 extended vector size = 5 value of vec [0] = 0 value of vec [1] = 1 value of vec [2] = 2 value of vec [3] = 3 value of vec [4] = 4 value of v = 0 value of v = 1 value of v = 2 value of v = 3 value of v = 4

13 Here are following points to be noted related to various functions we used in the above example: The push_back( ) member function inserts value at the end of the vector, expanding its size as needed. The size( ) function displays the size of the vector. The function begin( ) returns an iterator to the start of the vector. The function end( ) returns an iterator to the end of the vector. 4. Write a C++ program that reads a text file and creates another file that is identical except that every sequence of consecutive blank spaces is replaced by a single space. (8) [M/J 16 ] #include<fstream.h> #include<iostream.h> #include<process.h> #include<conio.h> void main() clrscr(); ifstream file1; ofstream file2; charsfile[13],tfile[13]; cout<<"\nenter Source file name-"; cin>>sfile; cout<<"\nenter Target file name-"; cin>>tfile; file2.open(sfile); file2<<"\nmy Name is RAHUL KUMAR"<<endl; file2.close(); file1.open(sfile); file2.open(tfile); if(!file1) cerr<<" Some Error.."; exit(1); charvarch,p=file1.get(); while(!file1.eof()) file2.put(p); varch=file1.get();

14 if(p==' ' &&varch==' ') p=varch; varch=file1.get(); p=varch; cout<<"\ncopied..."; file1.close(); file2.close(); cout<<"\ntarget File Contents...\n"; file1.open(tfile); while(!file1.eof()) file1.get(varch); cout<<varch; file1.close(); getch(); /* OUTPUT Enter Source file name-source Enter Target file name-target copied... Target File Contents... My Name is RAHUL KUMAR */

15 5. Write short notes on C++ exception handling. (7) [N/D-16] (4) [M/J 15] An exception is a problem that arises during the execution of a program. A C++ exception is a response to an exceptional circumstance that arises while a program is running, such as an attempt to divide by zero. Exceptions provide a way to transfer control from one part of a program to another. C++ exception handling is built upon three keywords: try, catch, and throw. throw: A program throws an exception when a problem shows up. This is done using a throw keyword. catch: A program catches an exception with an exception handler at the place in a program where you want to handle the problem. The catch keyword indicates the catching of an exception. try: A try block identifies a block of code for which particular exceptions will be activated. It's followed by one or more catch blocks. Assuming a block will raise an exception, a method catches an exception using a combination of the try and catch keywords. A try/catch block is placed around the code that might generate an exception. Code within a try/catch block is referred to as protected code, and the syntax for using try/catch looks like the following: try // protected code catch( ExceptionName e1 ) // catch block catch( ExceptionName e2 ) // catch block catch( ExceptionNameeN ) // catch block You can list down multiple catch statements to catch different type of exceptions in case your try block raises more than one exception in different situations.

16 Throwing Exceptions Exceptions can be thrown anywhere within a code block using throw statements. The operand of the throw statements determines a type for the exception and can be any expression and the type of the result of the expression determines the type of exception thrown. Following is an example of throwing an exception when dividing by zero condition occurs: double division(int a, int b) if( b == 0 ) throw "Division by zero condition!"; return (a/b); Catching Exceptions The catch block following the try block catches any exception. You can specify what type of exception you want to catch and this is determined by the exception declaration that appears in parentheses following the keyword catch. try // protected code catch( ExceptionName e ) // code to handle ExceptionName exception Above code will catch an exception of ExceptionName type. If you want to specify that a catch block should handle any type of exception that is thrown in a try block, you must put an ellipsis,..., between the parentheses enclosing the exception declaration as follows: try // protected code catch(...) // code to handle any exception The following is an example, which throws a division by zero exception and we catch it in catch block. #include <iostream> using namespace std;

17 double division(int a, int b) if( b == 0 ) throw "Division by zero condition!"; return (a/b); int main () int x = 50; int y = 0; double z = 0; try z = division(x, y); cout<< z <<endl; catch (const char* msg) cerr<<msg<<endl; return 0; Because we are raising an exception of type const char*, so while catching this exception, we have to use const char* in catch block. If we compile and run above code, this would produce the following result: Division by zero condition! C++ Standard Exceptions C++ provides a list of standard exceptions defined in <exception> which we can use in our programs. These are arranged in a parent-child class hierarchy shown below:

18 Here is the small description of each exception mentioned in the above hierarchy: Exception std::exception std::bad_alloc std::bad_cast std::bad_exception std::bad_typeid std::logic_error std::domain_error Description An exception and parent class of all the standard C++ exceptions. This can be thrown by new. This can be thrown by dynamic_cast. This is useful device to handle unexpected exceptions in a C++ program This can be thrown by typeid. An exception that theoretically can be detected by reading the code. This is an exception thrown when a mathematically invalid domain is used std::invalid_argument This is thrown due to invalid arguments. std::length_error std::out_of_range This is thrown when a too big std::string is created This can be thrown by the at method from for example a std::vector and

19 std::runtime_error std::overflow_error std::range_error std::underflow_error std::bitset<>::operator[](). An exception that theoretically can not be detected by reading the code. This is thrown if a mathematical overflow occurs. This is occured when you try to store a value which is out of range. This is thrown if a mathematical underflow occurs. Define New Exceptions You can define your own exceptions by inheriting and overriding exception class functionality. Following is the example, which shows how you can use std::exception class to implement your own exception in standard way: #include <iostream> #include <exception> using namespace std; structmyexception : public exception const char * what () const throw () return "C++ Exception"; ; int main() try throwmyexception(); catch(myexception& e) std::cout<< "MyException caught" <<std::endl; std::cout<<e.what() <<std::endl; catch(std::exception& e) //Other errors This would produce the following result: MyException caught C++ Exception Here, what() is a public method provided by exception class and it has been overridden by all the child exception classes. This returns the cause of an exception.

20 6. Write a C++ program to write a set of characters to a file. (6 )[N/D- #include <iostream> #include <fstream> usingnamespacestd; int main() ifstream fin; fin.open("my-input-file.txt", ios::in); charmy_character ; intnumber_of_lines = 0; while (!fin.eof() ) fin.get(my_character); cout<<my_character; if (my_character == '\n') ++number_of_lines; cout<<"number OF LINES: "<<number_of_lines<<endl;

21 7. Write a program to implement stack operations using class template. (8) [M/J 15] #include<iostream> using namespace std; template<class T> class stack T* arr; static int top; public: stack(int); void push(t); T pop(); bool empty(); ; template<class T> int stack<t>::top = -1; template<class T> stack<t>::stack(int x) this->arr = new T(x); template<class T> void stack<t>::push(t a) this->arr[++top] = a; template<class T> T stack<t>::pop() T a = this->arr[top--]; return a; template<class T> bool stack<t>::empty() return (top==-1); int main()

22 stack<int> s(10); int i; for(i=0;i<10;i++) s.push(i); while(!s.empty()) cout<<s.pop()<<endl; return 0; 8. Write a template function to sort the elements of an array. (4) [M/J 15] #include <iostream> #include <time.h> #include <string> #include <iomanip> usingnamespacestd; template<class Item> voidbubble_sort(item a[], size_t size); template<class Item> void swap(item& a, Item& b); template<class Item> voiddisplay_array(item randnum, size_t size); int main() int *randnum; inta,b; int size; swap(item& a, Item& b); //NOT SURE IF WORKS YET, UNTESTED srand((unsigned)time(null)); cout<<"how many integers?"<<endl; cin>> size; size = size +1; randnum = newint [size]; for (int i = 1; i < size; i++) randnum[i] = 1+ rand() % 10;

23 display_array(randnum, size); cout<<"\n \n sorted..."<<endl; bubble_sort( a[], size); //ERROR //display_array(randnum, size); system("pause"); return 0; //============================= template<class Item> voidbubble_sort(item a[], size_t size) size_tidx, pass; for (pass=1; pass<=size; ++pass) for (idx=0; idx<=size-2; ++idx) if (a[idx] > a[idx+1]) swap(a[idx], a[idx+1]); template<class Item> void swap(item& a, Item& b) Item temp; temp = a; a = b; b = temp; template<class Item> voiddisplay_array(item randnum, size_t size) for ( int j = 1; j < size; j++ ) cout<<setw(16) <<randnum[ j ];

24 9.Write a program to write the text in a file. Read the text from the file, end of the file. Display the contents of file in reverse order. Append the contents to the existing file. Writing Data to a File #include <iostream> #include <string> #include <fstream> using namespace std; int main() ofstreamofileobject; // Create Object of Ofstream OFileObject.open ("D:\\ExampleFile.txt"); // Opening a File or creating if not present OFileObject<< "I am writing to a file opened from program.\n"; // Writing data to file cout<<"data has been written to file"; OFileObject.close(); // Closing the file Appending Data to an Existing File #include <iostream> #include <string> #include <fstream> using namespace std; int main() ofstreamofileobject; // Create Object of Ofstream OFileObject.open ("D:\\ExampleFile.txt", ios::app); // Append mode OFileObject<< "I am writing to a file opened from program.\n"; // Writing data to file cout<<"data has been appended to file"; OFileObject.close(); // Closing the file Reading Data from File #include <iostream> #include <fstream> #include <string> using namespace std; int main() stringlinesread; ifstreamifileobject ("D:\\ExampleFile.txt"); (10) [M/J 15]

25 if (IFileObject.is_open()) while ( getline (IFileObject, linesread) ) cout<<linesread<<endl; IFileObject.close(); elsecout<< "File cannot be read"; Reversing a file content #include <iostream> #include <fstream> #include <cstdlib> using namespace std; int main(intargc, char *argv[]) fstreaminout("test.txt", ios::in ios::out ios::binary); if(!inout) cout<< "Cannot open input file.\n"; return 1; long e, i, j; char c1, c2; e = 5; for(i=0, j=e; i<j; i++, j--) inout.seekg(i, ios::beg); inout.get(c1); inout.seekg(j, ios::beg); inout.get(c2); inout.seekp(i, ios::beg); inout.put(c2); inout.seekp(j, ios::beg); inout.put(c1); inout.close(); return 0;

26 10. Write a function template for finding the maximum value in an array. (8) [N/D-15] #include <iostream.h> #include <conio.h> template<class T> T findmin(t arr[],int n) int i; T min; min=arr[0]; for(i=0;i<n;i++) if(min >arr[i]) min=arr[i]; return(min); void main() clrscr(); intiarr[5]; charcarr[5]; doubledarr[5]; cout<<"integer Values \n"; for(int i=0; i < 5; i++) cout<<"enter integer value "<< i+1 <<" : "; cin>>iarr[i]; cout<<"character values \n"; for(int j=0; j < 5; j++) cout<<"enter character value "<< j+1 <<" : "; cin>>carr[j];

27 cout<<"decimal values \n"; for(int k=0; k < 5; k++) cout<<"enter decimal value "<< k+1 <<" : "; cin>>darr[k]; //calling Generic function...to find minimum value. cout<<"generic Function to find Minimum from Array\n\n"; cout<<"integer Minimum is : "<<findmin(iarr,5)<<"\n"; cout<<"character Minimum is : "<<findmin(carr,5)<<"\n"; cout<<"double Minimum is : "<<findmin(darr,5)<<"\n"; getch(); 11. Write a C++ program to handle a divide by zero exception. (8 )[N/D-15] #include<iostream.h> #include<conio.h> void main() inta,b,c; float d; clrscr(); cout<<"enter the value of a:"; cin>>a; cout<<"enter the value of b:"; cin>>b; cout<<"enter the value of c:"; cin>>c; try if((a-b)!=0) d=c/(a-b); cout<<"result is:"<<d; else

28 throw(a-b); catch(int i) cout<<"answer is infinite because a-b is:"<<i; getch(); Output: Enter the value for a: 20 Enter the value for b: 20 Enter the value for c: 40 Answer is infinite because a-b is: Write a class template to represent a stack of any possible data type. (8) [N/D-15] #include<iostream> using namespace std; /* Define a generic class to perform relational operation */ template<class T> class relational T x, y; public : relational(t var1, T var2) x = var1; y = var2; T getmin() return ((x < y)? x : y); T getmax() return ((x > y)? x : y);

29 ; int main() relational<int> r1(11, 17); // object r1 with integer data members relational<double> r2(7.1, 6.9); // 'T' is replaced with 'double' type int min = r1.getmin(); // get min value of object r1 double max = r2.getmax(); // get max value of object r2 cout<< "Minimum Element of object r1 : " << min <<endl; cout<< "Maximum Element of object r2 : " << max <<endl; return 0; 13. Write a program to illustrate the concept of re-throwing an exception.(8)[n/d-14] #include <iostream> using namespace std; void MyHandler() try throw hello ; catch (const char*) cout<< Caught exception inside MyHandler\n ; throw; //rethrow char* out of function int main() cout<< Main start ; try MyHandler(); catch(const char*) cout<< Caught exception inside Main\n ;

30 cout<< Main end ; return 0; Output : Main start Caught exception inside MyHandler Caught exception inside Main Main end 14. Write afunctiontemplate tofind the minimum value contained in an array. (8)[N/D-14] #include<iostream.h> #include<conio.h> template<class T> T minimum(t a[],int size) T min=a[0]; for(int i=0;i<size;i++) if(a[i]<min) min=a[i]; return min; int main()

31 int a[10],size,i,min1; float b[10],min2; clrscr(); cout<<"enter the size value:\n"; cin>>size; cout<<"enter the integer aray elements\n"; for(i=0;i<size;i++) cin>>a[i]; cout<<"enter the floating array elements\n"; for(i=0;i<size;i++) cin>>b[i]; min1=minimum(a,size); min2=minimum(b,size); cout<<"the minimum integer elements is:\n"; cout<<min1; cout<<"\nthe minimum floating elements is :\n"; cout<<min2; getch(); return 0;