?
Solved

How is the increment operator significant to C, C++, and Java?

Posted on 2003-11-19
7
Medium Priority
?
567 Views
Last Modified: 2008-03-17
How is the increment operator significant to C, C++, and Java?
Could you explain to me how it works and why it is important to have increment operator?
0
Comment
Question by:veerawudth
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
7 Comments
 
LVL 101

Accepted Solution

by:
mlmcc earned 172 total points
ID: 9784557
I'll give you a little of the history.

If you are familiar with why C was developed and the original platform then the increment and decrement operators make sense.

The original hardware platform had a hardware increment and decrement capability which was much faster than x = x + 1;

C was developed to write an operating system (specifically Unix)  Any chance at speed increases were taken.  Thus the birth of the ++ and - - operators.

With the speed of machines today I am not sure it is even implemented the same way.  C++ has it to maintain compatability with C.  Java grew out of C and C++ so it was included.

mlmcc
0
 
LVL 22

Assisted Solution

by:cookre
cookre earned 164 total points
ID: 9784641
That's one of the characteristics that led many folks to say that C was really just a long winded assembly language.  Many CPUs had a feature that minimized looping times by using bits in an instruction that activate automatic index register incrementation or decrementation either before or after the effective address for that instruction is calculated - without effecting instruction execution time.  Hence, for example, an assembly program's use of index register pre-incrementation would be echoed in a c program with ++i, post incrementation with i++, and similarly with --.

The construct i+=1 (as opposed to i=i+1), as mlmcc indicated, was added to allow compiler writers to make use of increment (and decrement) instructions, e.g.:
   inc i                
at the cost of just a single cycle, as opposed to
   la       a0,i
   aa,u   a0,1
   sa      a0,i

costing three cycles.
0
 
LVL 18

Assisted Solution

by:Cluskitt
Cluskitt earned 164 total points
ID: 9786530
The incremental operator is basically very handy for programming, regardless of its speed contribute. With the incremental factor you can, AT THE SAME TIME, make an output and an attribution. For example, printf("%i",i++); will print on the screen the value of i, and it will increment it. So, if i was 10 before that line, it will print 10 on the screen and i will have a new value of 11. Similarly, if you type, printf("%i",++i), and again assuming i was 10, it will first increment it, and then print the output to the screen, in this case, 11.
There are plenty of uses where the incremental operator is handy, and some where it's a wonderful thing. Also, there are some where it's just a way to make it different, or writing a bit less.
And it avoids the thing that most confuses newcomers to programming which is, i=i+1 (usual comments being, i=i+1<=>0=1, which makes no sense ;-)
0
 
LVL 101

Expert Comment

by:mlmcc
ID: 10319426
3 good explanations.

mlmcc
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Entering a date in Microsoft Access can be tricky. A typo can cause month and day to be shuffled, entering the day only causes an error, as does entering, say, day 31 in June. This article shows how an inputmask supported by code can help the user a…
In this post we will learn different types of Android Layout and some basics of an Android App.
Viewers will learn how to properly install Eclipse with the necessary JDK, and will take a look at an introductory Java program. Download Eclipse installation zip file: Extract files from zip file: Download and install JDK 8: Open Eclipse and …
With the power of JIRA, there's an unlimited number of ways you can customize it, use it and benefit from it. With that in mind, there's bound to be things that I wasn't able to cover in this course. With this summary we'll look at some places to go…
Suggested Courses

770 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question