1 / 9

Chapter 17 - PowerPoint PPT Presentation

Chapter 17. Templates. Generic Algorithms. Algorithms in which the actions or steps are defined, but the data types of the items being manipulated are not. Examples Of Generic Algorithm. Swap the values of two variables of the same data types Find the index of the smallest value in an array.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

PowerPoint Slideshow about ' Chapter 17' - maalik

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Chapter 17

Templates

Algorithms in which the actions or steps are defined, but the data types of the items being manipulated are not.

• Swap the values of two variables of the same data types

• Find the index of the smallest value in an array.

• Pair up 2 values

void swap (char& v1, char& v2)

{

char temp = v1;

v1 = v2;

v2 = v3;

}

void swap (int& v1, int& v2)

{

int temp = v1;

v1 = v2;

v2 = v3;

}

void double (double & v1, double & v2)

{

double temp = v1;

v1 = v2;

v2 = v3;

}

void swap (CAny& v1, CAny& v2)

{

CAny temp = v1;

v1 = v2;

v2 = v3;

}

template <class T>

void swap (T& v1, T& v2)

{

T temp = v1;

v1 = v2;

v2 = v3;

}

int main ()

{

int i1=1, i2=2;

swap (i1, i2);

char c1=‘a’, c2=‘A’;

swap (c1, c2);

}

• The words template <class T> tell the compiler this is a template for a generic data type T and that T is the parametized type which can be replaced by a defined data type.

• T must have all of the operations used in the template function.

int a[5], b[5];

… // Some code to fill up arrays

swap (a, b); // NO! There is no assignment operator for arrays

//Class template for a pair of values of type T

template <class T>

class Pair

{

public:

Pair();

Pair(T f, T s);

void setElement (intpos, T val);

T getElement (intpos);

private:

T first;

T second;

};

template <class T>

Pair<T>::Pair() {}

template <class T>

Pair<T>::Pair(T f, T s) {

first = f;

second = s;

}

template <class T>

void Pair<T>::setElement (intpos, T val) {

if (pos == 1)

first = val;

else

second = val;

}

template <class T>

T Pair<T>::getElement (intpos) {

if (pos == 1)

return first;

else

return second;

}

void main ()

{

Pair<int> scores;

Pair<char>seats(‘A’, ‘B’);

score.setElement(1, 3);

score.setElement(2, 5);

char mySeat

mySeat=seats.getElement(1);

}

• The words template <class T> tell the compiler this is a template for a generic data type T and that T is the parametized type which can be replaced by a defined data type.

• T is used as a type in all function definitions or parameters of the class template.

• You can use typedef to improve readability.

typedef Pairs<int> PairsOfInt;

then declare PairsOfInt score;

• Type T is specialized by giving a type argument to the class name in place of the T.