Page 316 - DCAP404 _Object Oriented Programming

Unit 14: Advanced Concept in C++

Strcpy ( Ihs , rhs) ; Notes
Strcpy ( rhs , tmp ) ;
}

14.5 Point of Instantiation

A template function gets instantiated under the following circumstances:
1. Implicitly instantiated because it is referenced from a function call that depends on a
template argument.
2. Implicitly instantiated because it is referenced within a default argument in a declaration.
3. The point of instantiation of a function template specialization immediately follows the
declaration or definition that refers to the specialization.

Self Assessment

Fill in the blanks:
6. Error isolation is useful for locating an error resulting in a ....................... message.
7. The goal of object-oriented software development is to construct a model of ..................... .

8. ....................... activities are those activities that take place simultaneously.

14.6 Error Handling

We now know the syntactic errors and execution errors usually produce error messages when
compiling or executing a program. Syntactic errors are relatively easy to find and correct, even
if the resulting error messages are unclear. Execution errors, on the other hand, can be much
more troublesome. When an execution error occurs, we must first determine its location (where
it occurs) within the program. Once the location of the execution error has been identified, the
source of the error (why it occurs) must be determined. Location of the execution error occurred
often assists, however, in recognizing and correcting the error.
Closely related to execution errors are logical errors. Here the program executes correctly,
carrying out the programmer’s wishes, but the programmer has supplied the computer with
instructions that are logically incorrect. Logical errors can be very difficult to detect, since the
output resulting from a logically incorrect program may appear to be error-free. Moreover,
logical errors are often hard to locate even when they are known to exist (as, for example).
Methods are available for finding the location of execution errors and logical errors within a
program. Such methods are generally referred to as debugging techniques. Some of the more
commonly used debugging techniques are described below.
14.7 Error Isolation

Error isolation is useful for locating an error resulting in a diagnostic message. If the general
location of the error is not known, it can frequently be found by temporarily deleting a portion
of the program and then rerunning the program to see if the error disappears. The temporary
deletion is accomplished by surrounding the instructions with comment markets (/* and */),
causing the enclosed instructions to become comments. If the error message then disappears, the
deleted portion of the program contains the source of the error.

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