Chapter 1, Problem 7E

Program Plan Intro

Templates and Macros:

Macros:

• A macro can be stated as a string that compiler would replace with the defined value.
  • Example: #define STRING "Value"
• Macros are not safe type, that is, float data is not accepted by a macro that is defined for integer operations. Type checking is not performed while expansion.
• Finding errors in macros is difficult.
• When a variable is post incremented or decremented, operation is been performed twice.

Templates:

• A template is a way of making functions with independency in data type. Macros could not accomplish this task.
  • Example: A sorting function does not bother the type of data it is sorting, since the applied algorithm is same.

Syntax for Templates and Macros:

The syntax for template definition is shown below

Syntax for template:

template <class type>

type class-name<type>:: macro_name(arguments)

{

}

The syntax for macro definition is shown below

Syntax for macro:

#define macro_name replacement-text

return-type main()

{

  Variable-name = macro_name(arguments);

}

Expansion is performed twice for the above macro. It denotes a limitation of macros. All occurrences of macro in file would be replaced by “replacement-text” before compilation of program. The template removes the macro limitations.