Answer / naresh lingampally

Variables defined local to a function disappear at the end
of the function scope. So when we call the function again,
storage for variables is created and
values are reinitialized.

Static variables:
So if we want the value to be extent throughout the life of
a program, we can define the local variable as "static."
Initialization is performed only at the first call and data
is retained between func calls.

REGISTER VARIABLE :

Register variables are a special case of automatic
variables. Automatic variables are allocated storage in the
memory of the computer; however, for most computers,
accessing data in memory is considerably slower than
processing in the CPU. These computers often have small
amounts of storage within the CPU itself where data can be
stored and accessed quickly. These storage cells are called
registers.

Normally, the compiler determines what data is to be stored
in the registers of the CPU at what times. However, the C
language provides the storage class register so that the
programmer can ``suggest'' to the compiler that particular
automatic variables should be allocated to CPU registers, if
possible. Thus, register variables provide a certain control
over efficiency of program execution. Variables which are
used repeatedly or whose access times are critical, may be
declared to be of storage class register.

Also these register variables are used in huge projects the
tiny program developers are not interested to include these
register variables, because the tiny programs never requires
more time complete its job. These register variables may be
used to store constant values so as to make use of it
anywhere in the programs.

main{ register float a=0;}

Answer / koti pendem

static variables stored in initialised data segment,where as
register variables stored in registers

Answer / amit

static variable stored in RAM where as register variable
stored in CPU's register ,
we can find address of static variable which is not
possible in case of register variable

how to find binary of number?

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How do I send escape sequences to control a terminal or other device?

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i want the code for printing the output as follows 4 4 3 3 2 2 1 1 0 1 1 2 2 3 3 4 4

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what is the difference b/w compiler and debugger?

2 Answers   Assurgent,

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What is an operator?

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Is c call by value?

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The % symbol has a special use in a printf statement. Explain how would you place this character as part of the output on the screen?

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dynamically allocate memory for linear array of n integers,store some elements in it and find some of them

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I need help with the following lab. Can anyone explain it to me on how to approach this problem. Coding would be great too !!! No busy waiting allowed. Remember that Java monitors are 'signal and continue'. The input data is called the database (DB). In this problem, it consists of a single variable initialized in the main thread, to contain the current time of day in HH:MM:SS:mmm format (mmm is milliseconds) truncated to 3 digits. Threads follow these rules: 1. Readers may all attempt to read at the same time, but NOT if a writer is writing (i.e.; the writer is in the monitor. 2. Writing is exclusive (only 1 writer at a time, no readers while writing). 3. Options: (to be specified by instructor) a. Readers have absolute priority over writers. b. Writers have absolute priority over readers c. When a reader arrives and a writer is waiting, the reader is suspended behind the writer instead of being admitted immediately. Thus, a writer waits for readers that were running when it arrived, but does not to wait for new readers. You may program this in C++ or Java. There are 4 controlling input values: 1. r – number of readers 2. w – number of writers 3. R – delay for a reader to restart 4. W – delay for a writer to restart Create the following program consisting of 1 main process (your main program) with n threads: 1. The main thread: a. Creates the 'n' threads needed. Of these, r of them are readers and w of them are writers. Starts all readers and writers. b. Waits for all 'n' threads to complete. You may use any method to detect when they are all complete. c. Prints out the resulting outputs from the threads. 2. Threads: a. When a thread starts to run, it immediately tries to enter the monitor. b. A reader thread reads the DB, outputs the exact message below, then exits: >>> DB value read =: HH:MM:SS:mmm by reader number: rr where the underlined text is replaced with actual data. c. A writer thread updates the DB with a new value (from the system time), outputs the exact message below, then exits: *** DB value set to: HH:MM:SS:mmm by writer number: ww where the underlined text is replaced with actual data. d. Each thread accesses the data a total of 10 times, exiting, then re-entering the monitor after each access. Hints: 1. File access *might* not be thread-safe, so you should be prepared to handle this. Read the documentation for the language you are using. 2. Suggested values for delays are: a. If looping, R >=1,000,000 and W>=100,000 b. If using “sleep”, then R=100 ms, W=50 ms. Additional: • Thread output is to ONE file used by ALL threads (so you need to synchronize access to it). • Readers must provide sufficient delay that results are useful (delay by R before re-trying). R is another input value. • Writers must also delay. Delay by W, updating the DB each time. W is an input. • Test your program with AT LEAST TWO different sets of values for r and w (#s of readers and writers) plus this set: r = 4, w=2. Basic operation of a thread: attempt to enter the monitor. If unsuccessful, you get put on a queue. When you get in, read or write the data (depending on type of thread), exit the monitor, wait the required delay amount, then try again. Repeat 10 times.

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What are different storage class specifiers in c?

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2. What does static variable mean?

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Explain what are binary trees?

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