File Name: c programs on arrays and strings .zip
Complete Tutorial of Array in C
Arrays in C allow you to store multiple items of the same data type, such as a list of integers. Arrays form the basis for many data structures and allow you to build advanced programs. In this article, we are going to discuss what an array is and how you can use them, along with examples.
In C, an array is a way to store a fixed number of items of the same data type under a single name. You might think, why do we need arrays to store multiple data types, when you can just declare normal variables?
Let us take an example — suppose, you have been asked to write a program that takes in the temperature for the last 90 days and perform some processing on that data. With enough time and patience, you can declare 90 integer variables such as a1 , a2 , a3 and so on to store this information.
However, processing the information in these 90 variables is nearly impossible. What if you wanted to know the average temperature between a range of days such as the 10th and 25th day , where this range would be given by the user? You can store all the temperature values under a single variable like a , and then extract any set of values from it by using the index.
To declare an array, you simply need to specify the data type of the array elements, the variable name and the array size. This statement allocates a contiguous block of memory for four integers and initializes all the values to 0. This is how it is laid out in memory:. Array indexes start from zero and end with array size — 1.
So for the above array, you can use the first element with a , second element with a , third element with a and fourth last element with a. Apart from the square brackets to indicate the index, array elements behave like normal variables. So, for example, you can print them by using:. You can see the full program in action below, or download it here.
However, if you know the elements of the array, then there is an easier way to declare the array. This statement will automatically create an array of size 4, and initialize a to 10, a to 20 and so on. To confirm that this works, you can print the variables, just like we did in our previous program.
In this case, the rest of the elements are initialized with zero. In our above example, elements from a to a will be initialized, whereas a and a will be set to zero. Again, you can easily verify this by writing a program:. The C compiler automatically guesses the size of the array from the size of the initializer list. However, you cannot skip both the size and the initializer list, and write int a;. Arrays in C are of a fixed size, and so their size must be known when you create the array.
Therefore, if you skip both of them, C cannot create the array, and this will lead to a compile-time error. Previously, we have learnt how you can use the individual elements of an array.
Since the array indexes are integers starting from 0 to array size — 1 , you can use loops to visit all the elements of the array. Here is a very simple example. It initializes an array and prints each array element and the index:. Inside the for loop, we print the value of a[i].
So, in the first iteration, we print the value of a. In the second iteration, we print a. In this way, we print all the elements of the array. Now that we know the basics of an array, we will look at some basic programs that use arrays in C.
Let us begin with a simple program that reads five numbers into an array, and then prints them out. Here is the source code for the program, and you can download it here. In the first loop, we read numbers from the user and set it in the a[i] element. The elements of an array simply behave like regular variables. Sometimes, you may need to search for an element in an array. Linear search is a simple technique to search for an element.
In this program, we have declared an array a , the loop variable i , the element to search for search. We have also declared another variable pos , which keeps track of the array index where we found the element we were searching.
We iterate through each element of the array, and check if a[i] is equal to the value of search. If it is equal, we set the pos variable to the current index i , since we found the element at index i. Then, we compare the value of pos. The minimum value of an array index can be 0. These arrays are sometimes called one-dimensional 1D arrays. Just as int or float are data types, an array is also a data type.
These kinds of arrays are called two-dimensional 2D arrays. This statement allocates a contiguous block of memory. For our example, two 1D arrays combine together to form a 2D array, as you can see in the diagram below. Each 1D array can hold four integers. Also, just like 1D arrays, all the elements of the array are initialized to zero.
Now, let us see how we can access the elements of a 2D array. Since a 2D array consists of multiple 1D arrays, you need two indexes.
This is because, you need to specify the index of the 1D array, and the specific element inside that 1D array. A very common approach is to visualize 2D arrays like a table, where the first index is the row number and the second index is the column number. So, you can represent the above array as:.
This allows us to talk about 2D arrays in a much easier way. To use the element at the first row, third column, you can use a ; to use the element at the second row, second column, use a and so on. Apart from using two indexes, using 2D arrays is the same as using 1D arrays. A basic example of using the arrays is as follows:. You can find the full program below, or download it here.
If you know the elements beforehand, you can also use the initializer list syntax that we discussed previously. For example, if you want to make the following array:. You can write it as follows:. For easier understanding, you can also group the elements of the initializer list by using braces. For example, to initialize a 2D array with two rows and three columns, you can write:. You can also loop over, print, or ask for input using scanf as you would with 1D arrays.
Here is an example of initializing an array, and then using for loops to print the elements. You can download the code here. In the above program, we have used nested for loops to print the elements of the array. This is because a 2D array has two indexes, which means that the first and second index has to be changed individually.
Since the printf call uses a[i][j] , so, the outer loop with variable i changes the first index, i. The inner loop with variable j changes the column number. To understand this better, let us step through the loops.
After this, the inner loop value increases to 1, and similarly, we print a , a and a. Since 2D arrays can be visualized in the form of a table or matrix, all of our examples will revolve around the concept of using them for matrix operations. Before we look at more complex examples, let us first look at how to read numbers from the user into an array.
In the program, we begin by initializing an array of 10 rows and 10 columns, along with loop variables as well as variables that store the number of rows and columns requested by the user. Next, we ask the user to enter the number of rows and columns, and then we check if the number of rows and columns will fit into the 2D array.
Then, in the first nested for loop, we ask the user to enter the elements with scanf. The formula for transpose is as follows:. A matrix of size changes to a matrix of size. We can translate the above program into code quite easily. Suppose, the input array is a and the result array is b. Elements in a[i][j] will go into a b[j][i]. Just like our previous example, we declare the arrays are a and b respectively and have 10 rows and 10 columns to hold the input and result matrix.
Next, we ask the user to enter the rows and columns. If it exceeds the size of the array, we print an error and exit.
Then, we ask the user to enter the numbers one by one and print the input matrix. After that, we iterate through the matrix using a nested for loop, and implement the logic where a[i][j] goes to b[j][i]. As we discussed, the matrix size changes when you transpose it.
So, in the last loop, we use this idea and print all the elements of the matrix. In order to add two matrices, both must have the same number of rows and columns. The process of adding two matrices involves taking numbers from the same position of the matrix, adding them, and putting the result in the same position.
array programs in c for interview
Arrays in C allow you to store multiple items of the same data type, such as a list of integers. Arrays form the basis for many data structures and allow you to build advanced programs. In this article, we are going to discuss what an array is and how you can use them, along with examples. In C, an array is a way to store a fixed number of items of the same data type under a single name. You might think, why do we need arrays to store multiple data types, when you can just declare normal variables?
Download the tarball for this lab from the course website. These instructions are the same as in the lab2. Important : Make sure to put your name and any other information like any sources you used or collaborations you may have had in comments at the top of your source code. You should get into the habit of doing this for any source code you submit for this and probably every class. Submit electronically using the CS department submit server using the command:.
Mastering C Programming pp Cite as. In this chapter we will be concerned with pointers, arrays and strings. If you have done any programming before beginning to study C, you will have already encountered and used arrays and strings. If you have arrived here via assembly language programming, you will already be familiar with the concept of pointers. Pointers are one of the most important features of C and as such contribute to the flexibility and power for which the language is known. The concept of pointers is crucial to a clear understanding of the way arrays work, and strings are simply arrays of type char.
Lecture B3B36PRG – C Programming Language. Jan Faigl, B3B36PRG – Lecture Arrays, Strings, and Pointers. 1 /
String and Character Array
Remember that the C language does not support strings as a data type. A string is actually a one-dimensional array of characters in C language. These are often used to create meaningful and readable programs. If you don't know what an array in C means, you can check the C Array tutorial to know about Array in the C language. Before proceeding further, check the following articles:.
In this article, you will find several examples that uses strings in C programming. All examples mentioned in the page are related to strings in C programming. To understand all examples on this page, you should have the knowledge of:. Course Index Explore Programiz.
How to remove duplicates from a given array in C? Q How to remove duplicates from a given array in C? At this page we have covers all the Array coding questions in and previously asked in their Interview round or coding rounds. These programs can be asked from basics, array, string, pointer, linked list, file handling etc. I am an embedded c software engineer and a corporate trainer, currently, I am working as senior software engineer in a largest Software consulting company.
Initialization of C Array
C Array is a collection of variables belongings to the same data type. You can store group of data of same data type in an array. Output: value of arr is 10 value of arr is 20 value of arr is 30 value of arr is 40 value of arr is 50 2. Two dimensional array in C: Two dimensional array is nothing but array of array. Array declaration, initialization and accessing. Like it? Please Spread the word!
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