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

Criteria for selecting a theme for a project, Q. Criteria for selecting a t...

Q. Criteria for selecting a theme for a project? Topics for projects as we indicated earlier should emerge from the children's world. Teaching often becomes boring and unintere

Determine in brief about laptop computers, Laptop computers Laptop comp...

Laptop computers Laptop computers have the obvious advantage over desk-top computers (PCs) in that they are fully portable. This is of specific value if a user wishes to do wor

What is winchester technology, What is Winchester technology? The disk ...

What is Winchester technology? The disk and the read/write heads are placed in a sealed air-filtered enclosure known as Winchester technology.

Arbitrary categorisation - learning decision trees, Arbitrary categorisatio...

Arbitrary categorisation - learning decision trees: Through visualising  a set of boxes with some balls in. There if all the balls were in a single box so this would be nicely

Don''t care states, The conflict between too hot and too cold or too slow a...

The conflict between too hot and too cold or too slow and too fast can be resolved using don't care states. Don't care states are used when i) the state of the output is not

What are the types of pipeline hazards, What are the types of pipeline haza...

What are the types of pipeline hazards? The various pipeline hazards are:  1. Data hazard  2. Structural Hazard  3. Control Hazard.

What is a system call, What is a system call? A  system  call  is  a  r...

What is a system call? A  system  call  is  a  request  made  through  any  program  to  the  operating  system  for performing tasks, picked by a predefined set, that the said

Computers, Purpose: Front line client service. Make bookings for vehicle se...

Purpose: Front line client service. Make bookings for vehicle servicing, accesses client database, prints invoices for clients etc. The mechanics complete worksheets for the variou

Determine the values of the output of the logic gates, Write the values of ...

Write the values of the C output for the following gates: For a(n) ________ gate, the output is zero if any of the inputs are equal to  one. For a(n) ________ gate ,the

Define baud rate, Define baud rate The rate of data transfer in serial...

Define baud rate The rate of data transfer in serial data communication is signified in bps. Bits per second (bps) is the rate of transfer of information bits. Baud is the num

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