Defines a macro, Computer Engineering

Assignment Help:

Defines a macro

Defines a macro with the given name, having as its value the given replacement text. After that (for the rest of the current source file), wherever the preprocessor sees that name, it will replace it with the replacement text. The name follows the same rules as ordinary identifiers (it can contain only letters, digits, and underscores, and may not begin with a digit). Since macros behave quite differently from normal variables (or functions), it is customary to give them names which are all capital letters (or at least which begin with a capital letter). The replacement text can be absolutely anything--it's not restricted to numbers, or simple strings, or anything.

The most common use for macros is to propagate various constants around and to make them more self-documenting. We've been saying things like

char line[100];

...

getline(line, 100);

but this is neither readable nor reliable; it's not necessarily obvious what all those 100's scattered around the program are, and if we ever decide that 100 is too small for the size of the array to hold lines, we'll have to remember to change the number in two (or more) places.

A much better solution is to use a macro:

#define MAXLINE 100 char line[MAXLINE];

...

getline(line, MAXLINE);

 


Related Discussions:- Defines a macro

Give explanation about the use of SSL to secure the network, Give explanati...

Give explanation about the use of SSL to secure the network. SS L stands for Secure Sockets Layer is a protocol developed through Netscape for transmitting private document

Dynamic partitioning - computer architecture, Dynamic partitioning: To...

Dynamic partitioning: To rise above from difficulties with fixed partitioning, partitioning can be done dynamically, which called dynamic partitioning. Having it, the primary

Unix, A friend has promised to log in at a particular time. However, he nee...

A friend has promised to log in at a particular time. However, he needs to be contacted as soon as he logs in. The shell script checks after every minute whether he has logged in o

Why should i use xml, ? XML can be used to explain and recognize informatio...

? XML can be used to explain and recognize information accurately and unambiguously, in a way that computers can be programmed to? Understand? (Well, at least influence as if they

What is electronic cash, What is electronic cash? E-cash is cash that i...

What is electronic cash? E-cash is cash that is demonstrated by two models. One is on-line type of e-cash that allows for the completion of all kinds of internet transactions.

Calculate quantities from information in bayesian network, 1. A Bayesian ne...

1. A Bayesian network is shown for the variables paper Thickness, paper Alignment and Print Quality. The conditional probabilities are provided in the tables beside the nodes. Here

What is oo development, What is OO Development? OO development is a way...

What is OO Development? OO development is a way of thinking about software based on abstractions that exist in the actual world. Development refers to software lifecycle, desig

Explain resource request and allocation graph (rrag), Explain Resource requ...

Explain Resource request and allocation graph (RRAG) Deadlocks can be explained by a directed bipartite graph known as a Resource-Request-Allocation graph (RRAG).A graph G = (V

Define the information system, Define the Information System Growi...

Define the Information System Growing sophistication in products and markets is driving the organisational requirement for increasing amounts of information. This req

What are the main functions of sound cards, Q. What are the main functions ...

Q. What are the main functions of sound cards? Sound card (The card is frequently directly built into motherboards these days) is a board that has digital to analog sound conve

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd