Page 311 - DCAP404 _Object Oriented Programming

Object-oriented Programming

Notes
Example:

Template < class X >
X min ( X a , X b )
{
return (a < b ) ? a : b ;
}
This list of parameter types is called the formal parameter list of the template, and it cannot be
empty. Each formal parameter consists of the keyword, type name, followed by an identifier.
The identifier can be built-in or user-defined data type, or the identifier type. When the function
is invoked with actual parameters, the identifier type is substituted with the actual type of the
parameter. This allows the use of any data type. The template declaration immediately precedes
the definition of the function for which the template is being defined. The template declaration,
followed by the function definition, constitutes the template definition. The template of the max
( ) function is coded below:
# include < iostream.h >
template < class type >
type max ( type x , type y)
{
return x > y ? x : y ;

}
int main ( )
{
cout << “ max ( ‘A’, ‘a’) : “ << max ( ‘A’, ‘a’) << endl ;
cout << “ max ( 30, 40 ) : “ << max ( 30 , 40) << endl;
cout << “ max ( 45 . 67F, 12 . 32 F) : “ << max (45. 67F, 12 .
32 F) <,
endl;
return 0 ;
}
Output
max ( ‘A‘ , ‘a‘) : a
max ( 30 , 40 ) : 40

max ( 45.67F, 12 . 32F ) : 45 . 67
In the example, the list of parameters is composed of only one parameter. The next line specifies
that the function takes two arguments and returns a value, all of the defined in the formal
parameter list. See what happens if the following command is issued, keeping in mind the
template definition for max ( ) :
max ( a , b ) ;

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