Object Oriented Programming using C++: C++ Templates.pptx

Object Oriented Programming using C++: C++ Templates

1. Object Oriented Programming Using Templates in C++ Engr. Rashid Farid Chishti [email protected] https://youtube.com/rfchishti https://sites.google.com/site/chishti International Islamic University H-10, Islamabad, Pakistan http://www.iiu.edu.pk 1

2. Templates are powerful features of C++ which allows us to write generic programs. There are two ways we can implement templates : Function Templates Class Templates Similar to function templates, we can use class templates to create a single class to work with different data types . Class templates come in handy as they can make our code shorter and more manageable . C++ Class Templates Templates Function Templates Class Templates

3. #include < iostream > #include < stdlib.h > using namespace std ; int add( int a, int b){ return a + b; } double add( double a, double b){ return a + b; } int main(){ int iA = 3, iB = 4; double dA = 3.4, dB = 4.3; cout << iA << " + " << iB << " = " << add(iA, iB) << endl; cout << dA << " + " << dB << " = " << add ( dA , dB) << endl ; system ( "PAUSE " ); return 0; } 3 Example 1: Function Overloading 1

4. #include < iostream > #include < stdlib.h > using namespace std ; template < typename T> T add (T a, T b){ return a + b; } int main(){ int iA = 3, iB = 4; double dA = 3.4, dB = 4.3; cout << iA << " + " << iB << " = " << add(iA, iB) << endl; cout << dA << " + " << dB << " = " << add ( dA , dB) << endl ; system ( "PAUSE" ); return 0; } 4 Example 2: One Argument Function Template 1

5. #include < iostream > #include < stdlib.h > using namespace std ; template < typename T > inline T const & Max(T const & a, T const & b){ return a < b ? b:a; } int main(){ int i = 39, j = 20; cout << "Max(" << i << "," << j<< ") = " << Max( i , j) << endl ; double d1 = 13.5, d2 = 20.7; cout << "Max(" <<d1<< "," << d2<< ") = " << Max(d1, d2) << endl ; system ( "PAUSE" ); return 0; } 5 Example 3 : Two Arguments Function Template 1

6. #include < iostream > #include < stdlib.h > using namespace std ; template < typename T> class Calculator { private : T num1, num2; public : Calculator(T n1, T n2) { num1 = n1; num2 = n2; } void Result(){ cout << "Numbers are: " << num1 << " and " << num2 << "." << endl ; cout << num1 << " + " << num2 << " = " << add() << endl; cout << num1 << " / " << num2 << " = " << divide() << endl; } T add(); T divide(); }; 6 Example 4 : Calculator using Class Template (1/2) 1

7. template < typename T> T Calculator<T> :: add () { return num1 + num2; } template < typename T> T Calculator<T> :: divide() { return num1 / num2; } int main () { Calculator < int > iCalc (5, 2); Calculator < double > dCalc (2.6, 1.2); cout << " Int Result:" << endl ; iCalc.Result (); cout << endl << "Double Result :" << endl ; dCalc.Result (); system ( "PAUSE" ); return 0; } 7 2 Example 4: Calculator using Class Template (2/2 )

8. #include < iostream > using namespace std ; const int SIZE = 3; // stack size template < typename T> class Stack { private : T stack_array [SIZE]; int top; public : Stack () { top = -1; } bool Is_Empty () { return top <= -1; } bool Is_Full () { return top >= SIZE-1; } void Push ( T data ); void Pop ( ); T Top(); }; template < typename T> void Stack<T> :: Push(T data) { if ( Is_Full () ) // if stack full, cout << "Error: Stack is full" << endl ; else stack_array [++top] = data; } 8 2 Example 5 : Stack Using Class Template (1/2)

9. template < typename T> void Stack <T> :: Pop() { if (! Is_Empty ()) top- -; } template < typename T> T Stack<T> :: Top() { if (! Is_Empty ()) return stack_array [top]; return NULL; } int main() { Stack< int > st ; int i = 1; while (! st.Is_Full ()){ st.Push ( i ++*11); } while (! st.Is_Empty ()){ cout << st.Top () << endl ; st.Pop (); } system ( "PAUSE " ); return 0; } 9 2 Example 5: Stack Using Class Template (1/2)

10. #include < iostream > #include < stdlib.h > using namespace std ; template < class T1, class T2> class Test_Class { T1 a; T2 b; public : Test_Class (T1 a1, T2 b2){ a = a1; b = b2; } void Test(T1 x, T2 y); void Show( ); }; 10 Example 6 : Using Two Templates in a Class (1/2) 1

11. template < class T1, class T2> void Test_Class <T1,T2> :: Test(T1 x, T2 y) { a = x; b = y; } template < class T1, class T2> void Test_Class <T1,T2> :: Show () { cout << a << " and " << b << endl ; } int main() { Test_Class < double , int > test1 (1.23, 123); Test_Class < int , char > test2 ( 200, 'Z' ); test1.Show (); test2.Show (); system ( "PAUSE" ); return 0; } 11 2 Example 6 : Using Two Templates in a Class (2/2)