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 is external procedures, Q. What is External Procedures? These proc...

Q. What is External Procedures? These procedures are written as well as assembled in separate assembly modules and afterwards linked together with the main program to form a bi

What is the difference between wire and register, What is the difference be...

What is the difference between wire and reg Wire Wire is used for designing combinational logic, as we all know that this type of logic cannot store a value.  As  you  can

Design an or to and gates combinational network, Design an OR to AND gates ...

Design an OR to AND gates combinational network and NAND only n/w for the following Boolean expression: A'BC'D + ABC'D' + A'B'CD' + A'BCD'

How many address bits are required to represent 4K memory, How many address...

How many address bits are required to represent 4K memory ? Ans. 12 address bits are required for representing 4K memory, as 4K = 2 2 x 2 10   = 2 12 Therefore 1K = 1024

CONVERT NUMBER TO ALPHABET, HOW TO CONVERT THE NUMBER INTO ALPHABET USING C...

HOW TO CONVERT THE NUMBER INTO ALPHABET USING C/C++ PROGRAM

Computational fluid dynamics, Q. Computational Fluid Dynamics? Computat...

Q. Computational Fluid Dynamics? Computational Fluid Dynamics: CFD was a FORTRAN like language developed in the early 70s at "Computational Fluid Dynamics Branch of Ames Resear

Explain the parallel data storage - application of flip flop, Explain the P...

Explain the Parallel Data Storage - application of flip flops? In digital systems, data are usually stored in groups of bits that represent numbers, codes, or other information

Design a half adder, Q. Design a half adder? In half adder inputs are: ...

Q. Design a half adder? In half adder inputs are: The augend let's say 'x' and addend 'y' bits. The outputs are sum 'S' and carry 'C' bits. Logical relationship betwee

Why pointer variable to a function as an argument, Why pointer variable som...

Why pointer variable sometimes desirable to pass a pointer to a function as an argument? Frequently, a called function needs to make changes to objects declared in the calling

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