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

What are different adder circuits you studied, Half Adder (for addition of ...

Half Adder (for addition of two bits) Full Adder (for addition of three bits) Carry look ahead adder Carry save adder Carry propagate adder

What is loader, What is loader? Loader is a system software which havin...

What is loader? Loader is a system software which having a set of utility programs. It will load the object program to the memory.

Define opcode and operands, Q. Define Opcode and Operands? The most com...

Q. Define Opcode and Operands? The most common fields which are found in instruction formats are: Opcode: (What operation to perform?)  An operation code field cal

What do you mean by instruction cycle, Q. What do you mean by instruction c...

Q. What do you mean by instruction cycle? We have considered the instruction execution in previous section. Now let's consider more about different types of instruction executi

What are priority queues, What are priority Queues? There are many queu...

What are priority Queues? There are many queues in which we can insert items or delete items from any of the position based on some property. Now, those queues based on the pro

Which analysis finds syntactic structure of source statement, An analysis, ...

An analysis, which determines the syntactic structure of the source statement, is called ? Ans. Syntax analysis that determines the syntactic structure of the source statement.

Explain vector-memory instructions, Vector-Memory Instructions When vec...

Vector-Memory Instructions When vector operations with memory M are carried out then these are vector-memory instructions. These instructions are referred with the subsequent f

Describe the uses of credit cards and smart cards, Credit cards and smart c...

Credit cards and smart cards Credit cards comprise a magnetic stripe on the back made up of iron-based particles in a plastic film. Stripe is split up into 3 tracks which a

Shape - elements of composition, Shape : A shape is any area that can b...

Shape : A shape is any area that can be perceived to have height and width. Shapes within an image can be created by the use of line, or by the edges created by variations in c

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