### How to compare strings in C#

If beta is zero, y does not have to be a valid input. Keep up the good work!!

## Using Pointers, Arrays, Structures and Unions in 8051 C Compilers

The stack is used internally by the. NET virtual machine CLR for keeping the variables of the program and the parameters of the called methods it is called program execution stack. The Abstract Data Type "Stack". The stack is a data structure, which implements the behavior " last in — first out " LIFO. As we saw with the cubes, the elements could be added and removed only on the top of the stack.

ADT stack provides 3 major operations: The data structure stack can also have different implementations, but we are going to consider two — dynamic and static implementation.

Static Stack Array-Based Implementation. Like with the static list we can use an array to keep the elements of the stack. We can keep an index or a pointer to the element, which is at the top. Unused buffer memory should be hold to ensure fast push and pop operations. Here is how we could imagine a static stack: Linked Stack Dynamic Implementation. For the dynamic implementation of stack we use elements, which keep a value and a pointer to the next element.

This linked-list based implementation does not require an internal buffer, does not need to grow when the buffer is full and has virtually the same performance for the major operations like the static implementation: When the stack is empty, the top has value null. When a new item is added, it is inserted on a position where the top indicates, after which the top is redirected to the new element.

Removal is done by deleting the first element, pointed by the top pointer. In C we could use the standard implementation of the class in.

It is implemented statically with an array , as the array is resized when needed. All basic operations for working with a stack are implemented: Stack Usage — Example. We are going to add several elements, after which we are going to print them on the console. As the stack is a " last in, first out " LIFO structure, the program is going to print the records in a reversed order. Here is its output: Correct Brackets Check — Example.

This means to check if the count of the opening brackets is equal to the count of the closing brackets and all opening brackets match their respective closing brackets. The specification of the stack allows us to check whether the bracket we have met has a corresponding closing bracket. When we meet an opening bracket, we add it to the stack. When we meet a closing bracket, we remove an element from the stack. If the stack becomes empty before the end of the program in a moment when we have to remove an element, the brackets are incorrectly placed.

The same remains if in the end of the expression there are elements in the stack. Here is a sample implementation: WriteLine "Are the brackets correct? Here is how the output of the sample program looks like: Are the brackets correct? The "queue" data structure is created to model queues, for example a queue of waiting for printing documents, waiting processes to access a common resource, and others. Such queues are very convenient and are naturally modeled via the structure "queue".

In queues we can add elements only on the back and retrieve elements only at the front. For instance, we would like to buy a ticket for a concert. If we go earlier, we are going to buy earlier a ticket. If we are late, we will have to go at the end of the queue and wait for everyone who has come earlier.

This behavior is analogical for the objects in ADT queue. Abstract Data Type "Queue". The abstract data structure "queue" satisfies the behavior " first in — first out " FIFO.

Elements added to the queue are appended at the end of the queue, and when elements are extracted, they are taken from the beginning of the queue in the order they were added. Thus the queue behaves like a list with two ends head and tail , just like the queues for tickets.

Like with the lists, the ADT queue could be implemented statically as resizable array and dynamically as pointer-based linked list. Static Queue Array-Based Implementation. In the static queue we could use an array for keeping the elements. When adding an element, it is inserted at the index, which follows the end of queue.

After that the end points at the newly added element. When removing an element, we take the element, which is pointed by the head of the queue. After that the head starts to point at the next element. Thus the queue moves to the end of the array. When it reaches the end of the array, when adding a new element, it is inserted at the beginning of the array.

That is why the implementation is called " looped queue ", as we mentally stick the beginning and the end of the array and the queue orbits it: Static queue keeps an internal buffer with bigger capacity than the actual number of elements in the queue. Like in the static list implementation, when the space allocated for the queue elements is finished, the internal buffer grows usually doubles its size.

The major operations in the queue ADT are enqueue append at the end of the queue and dequeue retrieve an element from the start of the queue. Linked Queue Dynamic Implementation. The dynamic implementation of queue ADT looks like the implementation of the linked list. Like in the linked list, the elements consist of two parts — a value and a pointer to the next element: However, here elements are added at the end of the queue tail , and are retrieved from its beginning head , while we have no permission to get or add elements at any another position.

Here we could indicate the type of the elements we are going to work with, as the queue and the linked list are generic types. Here are some of the most frequently used: Queue Usage — Example. After that we are going to retrieve all elements and print them on the console: Enqueue "Message One" ;.

Enqueue "Message Two" ;. Enqueue "Message Three" ;. Enqueue "Message Four" ;. You can see that the elements leave the queue in the order, in which they have entered the queue.

This is because the queue is FIFO structure first-in, first out. We could illustrate the process with the following figure: As you can see, the process lies in retrieving elements from the beginning of the queue and placing others in its end.

Here is how the output of the above program looks like: As you can see, stack and queue are two specific data structures with strictly defined rules for the order of the elements in them. We used queue when we expected to get the elements in the order we inserted them, while we used stack when we needed the elements in reverse order. Write a program that reads from the console a sequence of positive integer numbers.

The sequence ends when empty line is entered. Calculate and print the sum and the average of the sequence. Write a program, which reads from the console N integers and prints them in reversed order. The sequence ends when an empty line is entered. Print the sequence sorted in ascending order. Write a program to test whether the method works correctly.

Write a program, which removes all negative numbers from a sequence. Write a program that removes from a given sequence all numbers that appear an odd count of times.

Write a program that finds in a given array of integers in the range [0…] how many times each of them occurs. Write a program that finds the majorant of given array and prints it. If it does not exist, print "The majorant does not exist! We are given the following sequence: We are given N and M and the following operations: Write a program, which finds the shortest subsequence from the operations, which starts with N and ends with M.

Implement the operations for adding, removing and searching for an element, as well as inserting an element at a given index, retrieving an element by a given index and a method, which returns an array with the elements of the list. Implement the data structure " Deque ". This is a specific list-like structure, similar to stack and queue, allowing to add elements at the beginning and at the end of the structure.

Implement the operations for adding and removing elements, as well as clearing the deque. If an operation is invalid, throw an appropriate exception. Implement the structure "Circular Queue" with array, which doubles its capacity when its capacity is full. Implement the necessary methods for adding, removing the element in succession and retrieving without removing the element in succession.

Implement numbers sorting in a dynamic linked list without using an additional array or other data structure. Using queue, implement a complete traversal of all directories on your hard disk and print them on the console.

We are given a labyrinth of size N x N. Some of the cells of the labyrinth are empty 0 , and others are filled x. We can move from an empty cell to another empty cell, if the cells are separated by a single wall. Calculate and fill the labyrinth as follows: If some cell cannot be reached, fill it with " u ".

Scan the list with a for -loop 1 … n-1 while keeping two variables: At each loop iteration if the number at the left is the same as the current number, increase length. Remember the current start and length every time when the current length becomes better than the current maximal length.

Finally create a new list and copy the found sequence to it. Testing could be done through a sequence of examples and comparisons, e. Perform a left-to-right scan through all elements.

If the current number is positive, add it to the result, otherwise, skip it. For each element p count how many times p appears in the list with a nested for -loop. If it is even number of times, append p to the result list which is initially empty. Finally print the result list. With a single scan calculate count[p] the number of occurrences of p in the input sequence for each number p from the input sequence.

With another single scan pass though all numbers p and append p to the result only when count[p] is even. Make a new array "occurrences" with size Thus, at each index, where the value is not 0, we have an occurring number, so we print it. Sort the list and you are going to get the equal numbers next to one another. Scan the array by counting the number of occurrences of each number. Scan through the elements. At each step if the element at the top of the stack is different from the next element form the input sequence, remove the element from the stack.

Otherwise append the element to the stack. Finally the majorant will be in stack if it exists. Each time when we find any two different elements, we discard both of them. And this operation keeps the majorant the same and decreases the length of the sequence, right? If we repeat this as much times as possible, finally the stack will hold only elements with the same value — the majorant.

In the beginning add N to the queue. Repeat the same for the next element in a loop. At each step in the loop print M and if at certain point the queue size reaches 50, break the loop and finish the calculation. Use the data structure queue. Firstly, add to the queue N. Repeat the following in a loop until M is reached: Do not add numbers greater than M.

As optimization of the solution, try to avoid repeating numbers in the queue. It will hold to hold a single list node. Use singly linked list similar to the list from the previous task, but only with a field Previous , without a field Next. Just modify your implementation of doubly-linked list to enable adding and removing from both its head and tail. Another solution is to use circular buffer see http: When the buffer is full, create a new buffer of double size and move all existing elements to it.

When you reach the last index, you need to add the next element at the beginning of the array. For the correct calculation of the indices use the remainder from the division with the array length. When you need to resize the array, implement it the same way like we implemented the resizing in the " Static List " section.

Use the simple Bubble sort. We start with the leftmost element by checking whether it is smaller than the next one. If it is not, we swap their places. Then we compare with the next element and so on and so forth, until we reach a larger element or the end of the array. We return to the start of the array and repeat the same procedure many times until we reach a moment, when we have taken sequentially all elements and no one had to be moved.

The algorithm is very easy: After that, until the queue is empty, we remove the current directory from the queue, print it on the console and add all its subdirectories to the queue.

This way we are going to traverse the entire file system in breadth. If there are no cycles in the file system as in Windows , the process will be finite. If in the solution of the previous problem we substitute the queue with a stack , we are going to get traversal in depth DFS.

After the queue is empty, we traverse the whole matrix and if in some of the cells we have 0, we fill it with " u ". Download the demo examples for this chapter from the book: Comment the book and the tasks in the: I was wondering if you ever thought of changing the layout of your site?

Its very well written; I love what youve got to say. But maybe you could a little more in the way of content so people could connect with it better. Youve got an awful lot of text for only having 1 or two images. My web page … garage door repair. Do you know if they make any plugins to safeguard against hackers? Is your theme custom made or did you download it from somewhere?

A design like yours with a few simple tweeks would really make my blog stand out. Please let me know where you got your design. Keep posting such kind of information on your blog. Im really impressed by your blog.

Hello there, You have performed an excellent job. I will certainly digg it and for my part suggest to my friends. There are several benefits of going in for outsourced web hosting support services. They carryout pay per click method and use inbound and outbound links for getting more traffic per day.

You can choose to dismiss the choice or you can prepare accordingly for a busy and profitable future. You really understand to concept. I have found this to be one of the best explanations so far. Please send me the PDFs. This site uses Akismet to reduce spam. Learn how your comment data is processed. In This Chapter In this chapter we are going to get familiar with some of the basic presentations of data in programming: Fundamentals of Programming with C: January 13, at 3: June 30, at 8: July 20, at 4: July 22, at 8: July 23, at 1: August 2, at Clash of Lords 2 Hack download says: August 13, at 2: I want to pull the teams scores from worksheet 2 and place the data into column B in worksheet 1.

Blue Green Yellow chair 1 x x chair 2 x chair 3 x x x. Is anyone able to assist me? I know there has to be nested formulas in this combination but I am not sure which ones would work most efficiently.

I have a task that is a little more complicated. Lets see if someonr knows how to solve this. I am matching two different sets of data that may have some common matching numbers.

In the illustration above, we are applying the index match match to match two individual values to those in a matrix and get the desired result. I need to apply this to two different data sets and display the common values in a third data set. I am currently using the Index Match Match formula across several worksheets. However, the issue that I am having with my formula occurs when one of the worksheets that my Index Match Match formula uses to search through does not contain a match for the master sheet.

The formula works excellent if every worksheet has an entry that corresponds to the Master worksheet however not every worksheet will have a match to the master. Is there any way to choose the 2nd or 3rd matching column value for the column reference? Basically constructing table a from table b.. Just wondering, I have a data table with all the payroll information in columns and with account codes, however, some payroll categories are using the same account codes.

The added issue is that each person can be paid in different currencies and have different departments. I have to sum up all the cost centres and the currencies which are in rows and with the same account codes In column The way round it I have found is sumproduct where I can perform a multiple lookup for the columns and sum up all the tables with the given account codes.

I want to know if there is another way to do this calculation as sumproduct takes a long time to calculate and I am investigating if Index and Match formulas can give me a faster calculation. ABC Quoted lowest price in the above table Tranporter name need to be refelct in Next coloum can you write formula.

However, I have a question following on from this. Is it possible to use the same formula to display an exact value using two vertical conditions at either ends of a matrix and the horizontal condition in the matrix?

Using your matrix in this tutorial [assume column 5 was replaced by a name of county from that state]. Is it possible to match a state vertical column to its corresponding county Vertical column before returning the exact value the result in a particular year Horizontal column?

I have a need to sum the values for a specific row. In the case of this articles data, the problem would look like this:.

Can I have the VBA code for what you have mentioned: I have been using Index match match in my deliverables workbook to consolidate data from my master file workbook. I have these in 2 different workbooks due to their massive size. My index match match on my deliverables file only returns data when the master data file is open otherwise I get a VALUE! I use Vlookup more often than I should… For complex models it turns very slow. This example was very helpful.

My one question is if the matching criteria are not exact values how would the formula change? What if the criteria you are looking for is a range of numbers.

From example one of the y axis columns is , and the next column is ,, I love how dynamic this allows excel to be. Hi my friend, Index Match Match is really a powerful tool. Hi all, I need the opposite of that.. Hi, This was a great explanation and I got it to work well!

Examples of the secondary worksheets being used to return data for the index match are called E, E, A, etc. This is working correctly, as long as I specifically name it in the formula which worksheet to us to use right now called E … I. The data I am working with has thousands of lookups to do across different worksheets in the same workbook. Is there any alternative to adding multiple Index Match functions together? For example, I have about 30 columns with numbers in them, and I am currently using Index Match when I have 3 or 4 dollar amounts to add together for the total.

However, I now need to add all 30 columns together to find the total for operating profit which is a row for example. I am using the following code in order to identify the Facility number associated with a facility.

I have 2 issues; firstly there are multiple facilities with the same or similar name and the code search requires an exact name to use for the search. How can I make the search more flexible to react on an incomplete name? I am adjusting the last 2 characters on eight extra lines to give me the 4 preceding and 4 post facilities based on the entered facility name however the requirement to enter the facility name exactly as it is in the database is very restrictive.

Grateful for any help or advice. This is my Master Data. Now, if Rest name and locality is match then it should give status in the third column. I need to fit an item to a selection of crates. Is there a variation of this formula that will allow me to find all of the crates with dimensions greater than the item? I have a table which has clients in one column who are assigned to a risk rating,in descending numeric order in another. I can do the index match but I do not want redundancies.

Piles — 1A-2Y, 1A-2X, would have an associated co-ordinate value i. Lets say i record North , East and Elv 99 for the same pile 1A-2y is this possible for excel to match the name of the pile in each data set then output the difference in the easting, northing and elevation?? Is it possible to use the matching function to look at multiple variables?

I am trying to build a quote spreadsheet that has to due with equipment and specs. My reference spreadsheet will have make, model, term, and price. So 3 variables have to match and then it will hopefully give me the price. There may be 4 or 5 variables that have to match thus giving the customer the sales price. This is to avoid having someone go through a massive option sheet and I am using a drop box format that will prefill the price and is linked to a large option spreadsheet.

Again, I want the price to fill automatically by the matching method. Suppose I want to do the exact opposite of what is done in the example. I want to search in a given column for an exact match and then return the value in the corresponding row. How do I do that? I would like to mention that I have several cells in the column that have exactly the same entry.

I would like to seperate the search for each of these cells and return the corresponding values of the rows seperately. My Excel connects manners of transport to certain destinations. The manners of transport are seperated in different columns and the destinations in rows. Thank you very much for this detailed explanation. Matthew, thank you so much for this! This is absolutely genius!!

Hi, I am using an Index and Match function. The bonus is a set amount depending on which group the employee is in and when their hire date was. How can I get an index match formula to look up a group based on a hire date and return the correct bonus amount?

All you have to do is, for the hire date, use the approximate match option. When referencing the hire ranges, just make sure to use the lower bound when doing the lookups. This is all based off the assumption that there are no breaks in your hire date ranges. Could you help me with an issue? The data file has data in this format: I need your help.

I am looking for a formula that can search a value in a table or a list and give me the header of the value that i am looking for. If I have data as per below: Pen Results in B5: I have the same question as Mahmoud Ahmed. So the formula needs to find the home team In a row , the away team in a column and allocate the score to that cell.

Matthew, thank you so much! For that matter, your Excel tutorials are simply the best! I love this site and will share with my associates! Hi, this is a nice formula and very clearly explained. However, it does not help me as I need to cross reference 3 criteria in 3 columns and 2 criteria in 2 rows to return a number. My file has in column A cost centres, column B regions and column C type of expense.

Across row 1 I have category like budget, actual, forecast and row two, qtr 1, qtr 2, etc. I am trying to summarise on the front sheet each cost centre per region per expense type but also if it is budget, actual or forecast and what quarter. This has been giving me headaches as I do not want to do this in numerous steps and open it to error.

Each client has many service dates and I want to select the first service date that belongs to the client. Client 1 has 4 rows with 4 service dates Jan , Feb , Mar and Apr I am able to sort the data range so that the first service date is the top row for each client.

I want some sort of formula that pulls Client 1 Jan and that I can run it for all the different clients. Any help would be much appreciated!! Hello, could you tell me if it is possible to use this formula to search a cell from sheet 1 to find its match on Sheet 2, then compare against an additional cell to return a date in a separate column?

On Sheet 2 a row contains the order , warehouse and the invoice date. The order is listed on 2 separate rows though because it is broken down by warehouse 1 and then warehouse 2. I cannot use vlookup due to the duplicate order numbers on sheet2 but have not been able to find a formula that can accomplish this yet. I have tried to get this to work on a fairly simple data set, but cannot seen to do so.

I want to lookup the day on which the maximum energy was generated from the following figures. The left hand column is the day. The maximum is It makes no difference if the cells are formatted as Numbers or General.

It works well for what I need. My question is when you set your range of the matrix can you use a table name instead of a range of cells so the index match match can be used to search the left most column and the header row of the specified table for the result also allowing for the matrix size to get bigger and not having to adjust the formula? Below is my database table. Below that is my horizontal and vertical references just above the outcome.

I am trying to figure out how to incorporate a 2nd horizontal option. I need to be able to A. I also copied my whole formula at the very bottom. I am using the formula to match dates from 2 sheets and give me a certain value. Is there a way to use this formula to look up values from more than one sheet? This does not, however, allow me to update my recap workbook when the source workbook Excel Formulas IIA is closed.

What a great tool! Question Though- I used list boxes for my vertical and horizontal lookup. Some of the outputs are formatted in dollars and some general numbers or dates. How to I get the formatting to carry back to the output of the lookup?

I am trying to create a formula using a number in cell B1 and the data in a range of cells in column B on one worksheet and finding the result in another worksheet. The problem is, I want excel to find the number shown in B1, which could be in any column on row one of another sheet and then finding the result for the next lookup criteria, which could be in one of two places….

In column D of one worksheet, row 19, I want to find the result for the following: