<![CDATA[VU Help - C++ Programing]]> https://vuhelp.net/ Tue, 27 Oct 2026 21:13:52 +0000 MyBB <![CDATA[c++ program on unix]]> https://vuhelp.net/Thread-c-program-on-unix Wed, 10 Oct 2012 04:16:37 -0400 varup]]> https://vuhelp.net/Thread-c-program-on-unix at di erent locations connected to the \Fall-OS" hotel's database.
Suppose each customer is represented by a process and the body of the process consists of all the
reservations made by that customer. A customer can make reservations, payments cancellation of
reservations/payments. Two or more customers may be doing the same transactions at around the
same time. Obviously, reservations/payments to the same room/time period must be performed
atomically (mutual exclusively). If a customer tries to reserve a room that has already been taken,
then disallow this action and print a "room taken" message. If a transaction tries to operate a
non-existent room, print an error message. A customer can reserve a contiguous or non-contiguous
block of two or more rooms at the same time.
To ensure these concurrent operations yield correct results, you are to use Unix semaphores to
control access to rooms/stay periods, which are stored in shared variables.
To simulate (1) the transmission delay between the hotel's central computer and a customer's
computer, and (2) the processing of each transaction, the rst four lines in the body of each
customer specify the required total execution time (in milliseconds) for each of the three operations
performed at that customer. In your implementation, each speci ed time is the length of the critical
section for the corresponding transaction.
Valid transactions are:
reserve (room_number) begin_date number_of_days name_of_customer
cancel (room_number) begin_date number_of_days name_of_customer
reserve (room_number1,...,room_numberK) begin_date number_of_days name_of_customer
/* non-contiguous block */
cancel (room_number1,...,room_numberK) begin_date number_of_days name_of_customer
reserve (room_number1-room_numberM) begin_date number_of_days name_of_customer
/* contiguous block */
cancel (room_number1-room_numberM) begin_date number_of_days name_of_customer
check customer_name /* show rooms and stay periods reserved */
Example{reserving a non-contiguous block of rooms:
reserve (2,5,58) ...
Example{reserving a contiguous block of rooms:
reserve (8-15) ...
You can cancel a room reservation only after you have reserved it. The input is as follows:
n /* number of rooms, numbered from 1 to n */
m /* number of customers */
customer_1:
reserve reserve_time (in milliseconds)
cancel cancel_time (in milliseconds)
check check_time (in milliseconds)
:
valid operations
:
end.
:
:
customer_m:
reserve reserve_time (in milliseconds)
cancel cancel_time (in milliseconds)
check check_time (in milliseconds)
:
valid operations
:
end.
The output after completing all transactions is: a report showing the transactions and resulting
room assignments with customer names.]]> at di erent locations connected to the \Fall-OS" hotel's database.
Suppose each customer is represented by a process and the body of the process consists of all the
reservations made by that customer. A customer can make reservations, payments cancellation of
reservations/payments. Two or more customers may be doing the same transactions at around the
same time. Obviously, reservations/payments to the same room/time period must be performed
atomically (mutual exclusively). If a customer tries to reserve a room that has already been taken,
then disallow this action and print a "room taken" message. If a transaction tries to operate a
non-existent room, print an error message. A customer can reserve a contiguous or non-contiguous
block of two or more rooms at the same time.
To ensure these concurrent operations yield correct results, you are to use Unix semaphores to
control access to rooms/stay periods, which are stored in shared variables.
To simulate (1) the transmission delay between the hotel's central computer and a customer's
computer, and (2) the processing of each transaction, the rst four lines in the body of each
customer specify the required total execution time (in milliseconds) for each of the three operations
performed at that customer. In your implementation, each speci ed time is the length of the critical
section for the corresponding transaction.
Valid transactions are:
reserve (room_number) begin_date number_of_days name_of_customer
cancel (room_number) begin_date number_of_days name_of_customer
reserve (room_number1,...,room_numberK) begin_date number_of_days name_of_customer
/* non-contiguous block */
cancel (room_number1,...,room_numberK) begin_date number_of_days name_of_customer
reserve (room_number1-room_numberM) begin_date number_of_days name_of_customer
/* contiguous block */
cancel (room_number1-room_numberM) begin_date number_of_days name_of_customer
check customer_name /* show rooms and stay periods reserved */
Example{reserving a non-contiguous block of rooms:
reserve (2,5,58) ...
Example{reserving a contiguous block of rooms:
reserve (8-15) ...
You can cancel a room reservation only after you have reserved it. The input is as follows:
n /* number of rooms, numbered from 1 to n */
m /* number of customers */
customer_1:
reserve reserve_time (in milliseconds)
cancel cancel_time (in milliseconds)
check check_time (in milliseconds)
:
valid operations
:
end.
:
:
customer_m:
reserve reserve_time (in milliseconds)
cancel cancel_time (in milliseconds)
check check_time (in milliseconds)
:
valid operations
:
end.
The output after completing all transactions is: a report showing the transactions and resulting
room assignments with customer names.]]> <![CDATA[how many malloc ,calloc and realloc take arguments in c++]]> https://vuhelp.net/Thread-how-many-malloc-calloc-and-realloc-take-arguments-in-c Wed, 20 Jun 2012 06:57:31 -0400 Vuhelper]]> https://vuhelp.net/Thread-how-many-malloc-calloc-and-realloc-take-arguments-in-c [SIZE="4"]in C++ malloc take 1 argument
,calloc take two argument
and realloc take two arguments [/SIZE]]]> [SIZE="4"]in C++ malloc take 1 argument
,calloc take two argument
and realloc take two arguments [/SIZE]]]> <![CDATA[how to check include library in Dev C++]]> https://vuhelp.net/Thread-how-to-check-include-library-in-Dev-C Sat, 09 Jun 2012 04:18:56 -0400 Vuhelper]]> https://vuhelp.net/Thread-how-to-check-include-library-in-Dev-C Open Dev.CPP folder and inside there is include folder open this folder and you can see all Header files include . the extension of these file are .h .Do not change the .h Extension file other wise there is problem in Code ..You can include your own librarys]]> Open Dev.CPP folder and inside there is include folder open this folder and you can see all Header files include . the extension of these file are .h .Do not change the .h Extension file other wise there is problem in Code ..You can include your own librarys]]> <![CDATA[how to use system("pause"); in Dec C++]]> https://vuhelp.net/Thread-how-to-use-system-pause-in-Dec-C Sat, 09 Jun 2012 04:14:00 -0400 Vuhelper]]> https://vuhelp.net/Thread-how-to-use-system-pause-in-Dec-C how to use system("pause"); in Dec C++ the code are given below

PHP Code:
#include<iostream>
#include<stdlib.h>
main ()
{
.
.
.
system("pause");
return 0;
} 
]]> how to use system("pause"); in Dec C++ the code are given below

PHP Code:
#include<iostream>
#include<stdlib.h>
main ()
{
.
.
.
system("pause");
return 0;
} 
]]> <![CDATA[Dangling Pointers Explain in C++]]> https://vuhelp.net/Thread-Dangling-Pointers-Explain-in-C Wed, 30 May 2012 11:52:19 -0400 Vuhelper]]> https://vuhelp.net/Thread-Dangling-Pointers-Explain-in-C Pointers that do not point to a valid object of the appropriate type. Dangling pointers arise when an object is deleted or deallocated, without modifying the value of the pointer, so that the pointer still points to the memory location of the deallocated memory. As the system may reallocate the previously freed memory to another process, if the original program then dereferences the (now) dangling pointer, unpredictable behavior may result, as the memory may now contain completely different data. This is especially the case if the program writes data to memory pointed by a dangling pointer, as silent corruption of unrelated data may result, leading to subtle bugs that can be extremely difficult to find, or cause segmentation faults.]]> Pointers that do not point to a valid object of the appropriate type. Dangling pointers arise when an object is deleted or deallocated, without modifying the value of the pointer, so that the pointer still points to the memory location of the deallocated memory. As the system may reallocate the previously freed memory to another process, if the original program then dereferences the (now) dangling pointer, unpredictable behavior may result, as the memory may now contain completely different data. This is especially the case if the program writes data to memory pointed by a dangling pointer, as silent corruption of unrelated data may result, leading to subtle bugs that can be extremely difficult to find, or cause segmentation faults.]]> <![CDATA[why we use inline function if there are simple function available, or what is the spa]]> https://vuhelp.net/Thread-why-we-use-inline-function-if-there-are-simple-function-available-or-what-is-the-spa Wed, 30 May 2012 11:51:36 -0400 Vuhelper]]> https://vuhelp.net/Thread-why-we-use-inline-function-if-there-are-simple-function-available-or-what-is-the-spa why we use inline function if there are simple function available, or what is the spacial benefit of inline function over simple function


A function is declared inline by using the inline function specifier or by defining a member function within a class or structure definition. The inline specifier is only a suggestion to the compiler that an inline expansion can be performed; the compiler is free to ignore the suggestion. The following code fragment shows an inline function definition.
inline int add(int i, int j)
{
return i + j;
}
An inline function is one for which the compiler copies the code from the function definition directly into the code of the calling function rather than creating a separate set of instructions in memory. Instead of transferring control to and from the function code segment, a modified copy of the function body may be substituted directly for the function call. In this way, the performance overhead of a function call is avoided.]]> why we use inline function if there are simple function available, or what is the spacial benefit of inline function over simple function


A function is declared inline by using the inline function specifier or by defining a member function within a class or structure definition. The inline specifier is only a suggestion to the compiler that an inline expansion can be performed; the compiler is free to ignore the suggestion. The following code fragment shows an inline function definition.
inline int add(int i, int j)
{
return i + j;
}
An inline function is one for which the compiler copies the code from the function definition directly into the code of the calling function rather than creating a separate set of instructions in memory. Instead of transferring control to and from the function code segment, a modified copy of the function body may be substituted directly for the function call. In this way, the performance overhead of a function call is avoided.]]> <![CDATA[how often do we require to use inline functions and macros. their importance in c++]]> https://vuhelp.net/Thread-how-often-do-we-require-to-use-inline-functions-and-macros-their-importance-in-c Wed, 30 May 2012 11:49:26 -0400 Vuhelper]]> https://vuhelp.net/Thread-how-often-do-we-require-to-use-inline-functions-and-macros-their-importance-in-c A function is declared inline by using the inline function specifier or by defining a member function within a class or structure definition. The inline specifier is only a suggestion to the compiler that an inline expansion can be performed; the compiler is free to ignore the suggestion. The following code fragment shows an inline function definition.
inline int add(int i, int j)
{
return i + j;
}
An inline function is one for which the compiler copies the code from the function definition directly into the code of the calling function rather than creating a separate set of instructions in memory. Instead of transferring control to and from the function code segment, a modified copy of the function body may be substituted directly for the function call. In this way, the performance overhead of a function call is avoided.

A symbol, name, or key that represents a list of commands, actions, or keystrokes. Many programs allow you to create macros so that you can enter a single character or word to perform a whole series of actions. As in the following example we are defining a macro with named PI and it will be replaced by the constant value 3.1415926 wherever PI is used in the program.
#define PI 3.1415926
Here the symbol PI will be replaced with the actual value (i.e. 3.1415926) in the program. These are simple macros like symbolic names mapped to constants.]]> A function is declared inline by using the inline function specifier or by defining a member function within a class or structure definition. The inline specifier is only a suggestion to the compiler that an inline expansion can be performed; the compiler is free to ignore the suggestion. The following code fragment shows an inline function definition.
inline int add(int i, int j)
{
return i + j;
}
An inline function is one for which the compiler copies the code from the function definition directly into the code of the calling function rather than creating a separate set of instructions in memory. Instead of transferring control to and from the function code segment, a modified copy of the function body may be substituted directly for the function call. In this way, the performance overhead of a function call is avoided.

A symbol, name, or key that represents a list of commands, actions, or keystrokes. Many programs allow you to create macros so that you can enter a single character or word to perform a whole series of actions. As in the following example we are defining a macro with named PI and it will be replaced by the constant value 3.1415926 wherever PI is used in the program.
#define PI 3.1415926
Here the symbol PI will be replaced with the actual value (i.e. 3.1415926) in the program. These are simple macros like symbolic names mapped to constants.]]> <![CDATA[what is heap and why we use it]]> https://vuhelp.net/Thread-what-is-heap-and-why-we-use-it Wed, 30 May 2012 11:48:51 -0400 Vuhelper]]> https://vuhelp.net/Thread-what-is-heap-and-why-we-use-it what is heap and why we use it


There are two places that stores items in memory as your code executes. These are Stack and the Heap. Both the stack and heap help us run our code. They reside in the operating memory on our machine and contain the pieces of information we need to make it all happen. Stack memory stores variable types in address' in memory, these variables in programming are called local variables and are often stored for short amounts of time while a function/method block uses them to compute a task. once a function/method has completed its cycle the reference to the variable in the stack is removed. Heap memory stores all instances or attributes, constructors and methods of a class/object. A Heap reference is also stored in Stack memory until the life cycle of the object has completed. Inside the Heap reference all the contents of the object are stored whereas with a local variable only the variable contents are stored in the stack. When the data is washed out of ram then system cannot continue its work from the last end point instead it needs to recall the data into the memory to start processing.Examples of heap implementrion are given on the following links.
An Introduction to Data Structures with C++
Source Code for Data Structures and Algorithm Analysis in C++ (Second Edition)]]> what is heap and why we use it


There are two places that stores items in memory as your code executes. These are Stack and the Heap. Both the stack and heap help us run our code. They reside in the operating memory on our machine and contain the pieces of information we need to make it all happen. Stack memory stores variable types in address' in memory, these variables in programming are called local variables and are often stored for short amounts of time while a function/method block uses them to compute a task. once a function/method has completed its cycle the reference to the variable in the stack is removed. Heap memory stores all instances or attributes, constructors and methods of a class/object. A Heap reference is also stored in Stack memory until the life cycle of the object has completed. Inside the Heap reference all the contents of the object are stored whereas with a local variable only the variable contents are stored in the stack. When the data is washed out of ram then system cannot continue its work from the last end point instead it needs to recall the data into the memory to start processing.Examples of heap implementrion are given on the following links.
An Introduction to Data Structures with C++
Source Code for Data Structures and Algorithm Analysis in C++ (Second Edition)]]> <![CDATA[Default Function Argument with example]]> https://vuhelp.net/Thread-Default-Function-Argument-with-example Wed, 30 May 2012 11:47:13 -0400 Vuhelper]]> https://vuhelp.net/Thread-Default-Function-Argument-with-example Default function argument means to fix the value of one or more than one function parameters which you expect, will remain same in the entire or most of the program. For example you have a function named table() which takes two parameters number and upperlimit. Number is the value you want to print table of, and upperlimit contains the value upto which you want the table to be. In this case you will know that most of the time the value of upperlimit will be same i.e. 10, so you can fix this value.
table(int number, int upperlimit = 10);
Now whenever you call this function, the value of upperlimit will be 10 by default.
You can also call this function by only giving the parameter value for number variable only.]]> Default function argument means to fix the value of one or more than one function parameters which you expect, will remain same in the entire or most of the program. For example you have a function named table() which takes two parameters number and upperlimit. Number is the value you want to print table of, and upperlimit contains the value upto which you want the table to be. In this case you will know that most of the time the value of upperlimit will be same i.e. 10, so you can fix this value.
table(int number, int upperlimit = 10);
Now whenever you call this function, the value of upperlimit will be 10 by default.
You can also call this function by only giving the parameter value for number variable only.]]> <![CDATA[What is the difference among calloc function ,malloc function and recalloc function?]]> https://vuhelp.net/Thread-What-is-the-difference-among-calloc-function-malloc-function-and-recalloc-function Wed, 30 May 2012 11:46:25 -0400 Vuhelper]]> https://vuhelp.net/Thread-What-is-the-difference-among-calloc-function-malloc-function-and-recalloc-function 1- Two types of dynamic memory allocation one is calloc and other is malloc.
There are two differences. First is in the number of arguments. Malloc() takes a single argument (memory required in bytes), while calloc() needs two arguments.
malloc() does not initialize the memory allocated, while calloc() initializes the allocated memory to ZERO.

calloc() allocates a memory area, the length will be the product of its parameters. calloc fills the memory with ZERO's and returns a pointer to first byte. If it fails to locate enough space it returns a NULL pointer.

Syntax: ptr_var=(cast_type *)calloc(no_of_blocks , size_of_each_block); i.e. ptr_var=(type *)calloc(n,s); malloc() allocates a single block of memory of REQUSTED SIZE and returns a pointer to first byte. If it fails to locate requsted amount of memory it returns a null pointer.

Syntax:
ptr_var=(cast_type *)malloc(Size_in_bytes);
The malloc() function take one argument, which is the number of bytes to allocate, while the calloc() function takes two arguments, one being the number of elements, and the other being the number of bytes to allocate for each of those elements. Also, calloc() initializes the allocated space to zeroes, while malloc() does not.

If a pointer has already been allocated memory using malloc and later this allocated memory needs to be expanded for some reason, the realloc function is used. It will add the consecutive memory spaces to the existing if available, otherwise it will allocate whole new space for the same pointer.]]> 1- Two types of dynamic memory allocation one is calloc and other is malloc.
There are two differences. First is in the number of arguments. Malloc() takes a single argument (memory required in bytes), while calloc() needs two arguments.
malloc() does not initialize the memory allocated, while calloc() initializes the allocated memory to ZERO.

calloc() allocates a memory area, the length will be the product of its parameters. calloc fills the memory with ZERO's and returns a pointer to first byte. If it fails to locate enough space it returns a NULL pointer.

Syntax: ptr_var=(cast_type *)calloc(no_of_blocks , size_of_each_block); i.e. ptr_var=(type *)calloc(n,s); malloc() allocates a single block of memory of REQUSTED SIZE and returns a pointer to first byte. If it fails to locate requsted amount of memory it returns a null pointer.

Syntax:
ptr_var=(cast_type *)malloc(Size_in_bytes);
The malloc() function take one argument, which is the number of bytes to allocate, while the calloc() function takes two arguments, one being the number of elements, and the other being the number of bytes to allocate for each of those elements. Also, calloc() initializes the allocated space to zeroes, while malloc() does not.

If a pointer has already been allocated memory using malloc and later this allocated memory needs to be expanded for some reason, the realloc function is used. It will add the consecutive memory spaces to the existing if available, otherwise it will allocate whole new space for the same pointer.]]> <![CDATA[What is Function Overloading in C++]]> https://vuhelp.net/Thread-What-is-Function-Overloading-in-C Wed, 30 May 2012 11:45:30 -0400 Vuhelper]]> https://vuhelp.net/Thread-What-is-Function-Overloading-in-C Function overloading means defining multiple functions with same name but with different parameters. For example you may have a function sum() with 2 arguments and with three arguments such as
int sum(int a, int b);
int sum(double a, double b, int c);]]> Function overloading means defining multiple functions with same name but with different parameters. For example you may have a function sum() with 2 arguments and with three arguments such as
int sum(int a, int b);
int sum(double a, double b, int c);]]> <![CDATA[offline function in C++]]> https://vuhelp.net/Thread-offline-function-in-C Wed, 30 May 2012 11:42:16 -0400 Vuhelper]]> https://vuhelp.net/Thread-offline-function-in-C There is no term as offline function. The functions other than inline funtions are regular functions.]]> There is no term as offline function. The functions other than inline funtions are regular functions.]]> <![CDATA[i take input from getchar(); function in program in C++ 2012]]> https://vuhelp.net/Thread-i-take-input-from-getchar-function-in-program-in-C-2012 Wed, 30 May 2012 11:40:56 -0400 Vuhelper]]> https://vuhelp.net/Thread-i-take-input-from-getchar-function-in-program-in-C-2012 getchar() function takes a single character as input from user. You can store the character into a character variable or an array. For example if you have a character variable
char s;
then s = getchar(); statement will take one character from the user and store it in s.
Similarly you can get input in a character array using a loop where each iteration of loop will store one character in array's elements.]]> getchar() function takes a single character as input from user. You can store the character into a character variable or an array. For example if you have a character variable
char s;
then s = getchar(); statement will take one character from the user and store it in s.
Similarly you can get input in a character array using a loop where each iteration of loop will store one character in array's elements.]]> <![CDATA[what is meant by trivial and non trivial in C and C++ 2012]]> https://vuhelp.net/Thread-what-is-meant-by-trivial-and-non-trivial-in-C-and-C-2012 Wed, 30 May 2012 11:38:30 -0400 Vuhelper]]> https://vuhelp.net/Thread-what-is-meant-by-trivial-and-non-trivial-in-C-and-C-2012 Trivial and non-trivial refer to something (a statement) which is easy and not easy to prove. For example its a trivial fact that a character variable can store only one character at a time.


[COLOR="red"]
for more information check the C++ book[/COLOR]]]> Trivial and non-trivial refer to something (a statement) which is easy and not easy to prove. For example its a trivial fact that a character variable can store only one character at a time.


[COLOR="red"]
for more information check the C++ book[/COLOR]]]> <![CDATA[how we used the 1-calloc Function 2- malloc Function 3- free () 4- realloc Function i]]> https://vuhelp.net/Thread-how-we-used-the-1-calloc-Function-2-malloc-Function-3-free-4-realloc-Function-i Wed, 30 May 2012 11:35:07 -0400 Vuhelper]]> https://vuhelp.net/Thread-how-we-used-the-1-calloc-Function-2-malloc-Function-3-free-4-realloc-Function-i Define that how we used the 1-calloc Function 2- malloc Function 3- free () 4- realloc Function in C and C++ 2012- 14
]]> Define that how we used the 1-calloc Function 2- malloc Function 3- free () 4- realloc Function in C and C++ 2012- 14
]]>