One Dimensional Arrays in C

11 Key excerpts on "One Dimensional Arrays in C"

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  eBook - PDF

  Programming with C++

  • Kyla McMullen, Elizabeth Matthews, June Jamrich Parsons, , Kyla McMullen, Kyla McMullen, Elizabeth Matthews, June Jamrich Parsons(Authors)
  • 2021(Publication Date)
  • Cengage Learning EMEA

    (Publisher)

  When you design programs that handle two-dimensional arrays, use decomposition techniques to break down the algorithm into manageable chunks. For example, you can work out the algorithm for a one-dimensional array first, and then adapt it for a two-dimensional array. SUMMARY • An array is a data structure that stores a collection of elements that all have the same data type. Arrays are also classified as composite data types because they are constructed from primitive data types, such as integers or characters. • Arrays are homogeneous, ordered, and finite. They have a variety of use cases for working with collections of data. • Programmers typically work with one-dimensional and two-dimensional arrays. A one-dimensional array is linear. A two-dimensional array has rows and columns that form a matrix. • Both one-dimensional and two-dimensional arrays are stored in consecutive memory addresses. In program code, each element of an array is identified by an index value enclosed in brackets. • One-dimensional array elements have one index. Two-dimensional array elements have a row index and a column index. Index errors in program code are common but are easy to identify and correct. Figure 8-18 Sum the rows and columns in a two-dimensional array { column_sum = column_sum + magic_array[j][i]; } cout << setw(4) << column_sum; } cout << endl; } OUTPUT: 6 7 8 9 10 40 13 3 1 11 12 40 5 14 15 4 2 40 24 24 24 24 24 Copyright 2022 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. PROGRAMMING WITH C++ 144 • Accessing each array element in sequence is called traversing an array.

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  Data Structures and Program Design Using C

  A Self-Teaching Introduction

  • D. Malhotra, N. Malhotra(Authors)
  • 2018(Publication Date)
  • Mercury Learning and Information

    (Publisher)

  C H A P T E R 3 ARRAYS In This Chapter l Introduction l Definition of an array l Array declaration l Array initialization l Calculating the address of array elements l Analyzing an algorithm l Abstract data types l Declaration of two-dimensional arrays l Operations on 2-D arrays l Multidimensional arrays/ N-dimensional arrayys l Calculating the address of 3-D arrays l Arrays and pointers l Array of pointers l Arrays and their applications l Sparse matrices l Types of sparse matrices l Representation of sparse matrices l Summary l Exercises 78 • DATA STRUCTURES AND PROGRAM DESIGN USING C 3.1 Introduction We have already studied the basics of programming in data structures and C in the previous chapter in which we aimed to design good pro- grams, where a good program refers to a program which runs correctly and efficiently by occupying less space in the memory, and also takes less time to run and execute. Undoubtedly, a program is said to be efficient when it executes with less memory space and also in minimal time. In this chapter, we will learn about the concept of arrays. An array is a user-defined data type that stores related information together. Arrays are discussed in detail in the following sections. 3.2 Definition of an Array An array is a collection of homogeneous (similar) types of data ele- ments in contiguous memory. An array is a linear data structure because all elements of the array are stored in linear order. Let us take an exam- ple in which we have ten students in a class, and we have been asked to store the marks of all ten students; then we need a data structure known as an array. In the previous example, the data elements are stored in the succes- sive memory locations and are identified by an index number (also known as the subscript), that is, A i or A[i]. A subscript is an ordinal number which is used to identify an element of the array.

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  eBook - PDF

  An Introduction to Programming with C++

  • Diane Zak(Author)
  • 2015(Publication Date)
  • Cengage Learning EMEA

    (Publisher)

  C H A P T E R 11 One-Dimensional Arrays After studying Chapter 11, you should be able to:  Declare and initialize a one-dimensional array  Enter data into a one-dimensional array  Display the contents of a one-dimensional array  Pass a one-dimensional array to a function  Calculate the total and average of the values in a one-dimensional array  Search a one-dimensional array  Access an individual element in a one-dimensional array  Find the highest value in a one-dimensional array  Use parallel one-dimensional arrays  Explain the bubble sort algorithm Copyright 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. C H A P T E R 1 1 One-Dimensional Arrays 370 Arrays All of the variables you have used so far have been simple variables. A simple variable , also called a scalar variable , is one that is unrelated to any other variable in memory. Some programs, however, will require the use of variables that are related to each other. In those cases, it is easier and more efficient to treat the related variables as a group. You already are familiar with the concept of grouping. The clothes in your closet are probably separated into groups, such as coats, sweaters, shirts, and so on. Grouping your clothes in this manner allows you to easily locate your favorite sweater because you only need to look through the sweater group rather than through the entire closet. You may also have the songs on your MP3 player grouped by either music type or artist.

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  Data Structures and Program Design Using C++

  • D. Malhotra, N. Malhotra(Authors)
  • 2019(Publication Date)
  • Mercury Learning and Information

    (Publisher)

  3

  ARRAYS

  In This Chapter

  • Introduction

  • Definition of an array

  • Array declaration

  • Array initialization

  • Calculating the address of array elements

  • Analyzing an algorithm

  • Abstract data types

  • Declaration of two-dimensional arrays

  • Operations on 2-D arrays

  • Multidimensional arrays/ N-dimensional arrayys

  • Calculating the address of 3-D arrays

  • Arrays and pointers

  • Array of pointers

  • Arrays and their applications

  • Sparse matrices

  • Types of sparse matrices

  • Representation of sparse matrices

  • Summary

  • Exercises

  3.1Introduction

  We have already studied the basics of programming in data structures and C++ in the previous chapter in which we aimed to design good programs, where a good program refers to a program which runs correctly and efficiently by occupying less space in the memory, and also takes less time to run and execute. Undoubtedly, a program is said to be efficient when it executes with less memory space and also in minimal time. In this chapter, we will learn about the concept of arrays. An array is a user-defined data type that stores related information together. Arrays are discussed in detail in the following sections.

  3.2Definition of an Array

  An array is a collection of homogeneous (similar) types of data elements in contiguous memory . An array is a linear data structure because all elements of the array are stored in linear order. Let us take an example in which we have ten students in a class, and we have been asked to store the marks of all ten students; then we need a data structure known as an array.

  FIGURE 3.1 .

  Representation of an array of 10 elements.

  In the previous example, the data elements are stored in the successive memory locations and are identified by an index number (also known as the subscript), that is, Ai or A[i]. A subscript is an ordinal number which is used to identify an element of the array

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  Introduction to Computational Modeling Using C and Open-Source Tools

  • Jose M. Garrido(Author)
  • 2013(Publication Date)
  • Chapman and Hall/CRC

    (Publisher)

  Chapter 8 Arrays 8.1 Introduction An array stores multiple values of data with a single name and most program-ming languages include facilities that support arrays. The individual values in the array are known as elements . Many programs manipulate arrays and each one can store a large number of values in a single collection. To refer to an individual element of the array, an integer value or variable known as the array index is used after the name of the array. The value of the index repre-sents the relative position of the element in the array. Figure 8.1 shows an array with 13 elements. This array is a data structure with 13 cells, and each cell contains an element value. In the C programming language, the index values start with 0 (zero). FIGURE 8.1: A simple array. To use arrays in a C program the following steps are carried out: 1. Declare the array with appropriate name, size, and type 2. Assign initial values to the array elements 3. Access or manipulate the individual elements of the array In C, an array is basically a static data structure because once the array is de-clared, its size cannot be changed. The size of an array is the number of elements it can store. An array can also be created at execution time using pointers. A simple array has one dimension and is considered a row vector or a column vector. To manipulate the elements of a one-dimensional array, a single index is re-quired. A vector is a single-dimension array and by default it is a row vector. A matrix is a two-dimensional array and the typical form of a matrix is an array with data items organized into rows and columns. In this array, two indexes are used: one index to indicate the column and one index to indicate the row. Figure 8.2 shows 99 100 Introduction to Computational Modeling a matrix with 13 columns and two rows. Because this matrix has only two rows, the index values for the rows are 0 and 1. The index values for the columns are from 0 up to 12.

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  eBook - ePub

  C Programming

  Learn to Code

  • Sisir Kumar Jena(Author)
  • 2021(Publication Date)
  • Chapman and Hall/CRC

    (Publisher)

  This chapter is dedicated to a discussion of arrays. After completion of this chapter, readers will have learnt the following:

  • How to define an array and its type;
  • How to write code to declare different types of arrays, like 1D arrays and 2D arrays, and use them for solving problems;
  • Declaration, processing, and manipulation of strings (also known as character arrays).

  10.2 Need for Arrays

  A variable can hold one value at a time. There are situations in which we want to store more than one value at a time. Suppose we want to store the age of 100 persons and arrange them in a sorted manner. This type of problem can be solved by taking 100 variables, where each variable contains the age of a single person. But this is an inconvenient way to solve this problem. A more elegant way is to use an array. So, before we solve different types of problems, we should know the basic concept of an array.

  10.3 Types of Arrays

  According to the definition, an array is a collection of compartments. Further, we can say the elements of an array can be stored in a row of compartments, or can be stored in the form of a table. Depending upon the representation style and the type of data it contains, the array can be classified as shown in Figure 10.2 .

  Figure 10.2 Classification of arrays.

  A character array (string) is of the type 1D array (i.e., the array which contains only character data).

  10.4 1D Arrays

  A 1D array is a collection of items having common data types stored in a contiguous memory location, identified by a single name with its index number. More generally, suppose we have stored five different integers in a continuous memory location with a common name. We can access each integer with the help of the name of the array and index number – then the whole scenario is called an integer array.

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  Elementary Synchronous Programming

  in C++ and Java via algorithms

  • Ali S. Janfada(Author)
  • 2019(Publication Date)
  • De Gruyter Oldenbourg

    (Publisher)

  https://doi.org/10.1515/9783110616484-008 8 One-dimensional arrays 8.1 vectors In previous chapters, we addressed independent and non-homonymous variables in algorithm writing and programming. Now, we start working with variables named arrays which include one or more indices. These variables have the same name but different indices. In the process of solving certain problems, we have to deal with a large number of variables having similar behaviours in the program. In these situa-tions, defining all the variables independently consumes the time of the algorithm, increases its size and thus makes it useless. Therefore, we use arrays which have ho-monymous variables and different indices in order to overcome this problem. An im-portant advantage of using arrays is in object-oriented programming: arrays, as the predefined objects, pass by the reference. In the present chapter, we concentrate on one-dimensional arrays and remove the phrase “one-dimensional”. This type of array is occasionally regarded as a vector or a list. For example, an array of eight entries is illustrated in the following diagram. u u u u u u u u u[1] u[2] u[3] u[4] u[5] u[6] u[7] u[8] As shown, eight different variables exists in this diagram all having the same name while different indices. In theoretical studies, these variables are written as u 1 , u 2 , …, u 8 . All of the entries of an array should be of the same data type which is then asso-ciated with the array data type. For instance, an array is integer if all of its entries are integers. The declaration of arrays in programming is as follows. declaration of arrays in C++: declaration of arrays in Java: data type array name [ array length ] ; data type ˽ array name []=new ˽ data type [ array length ]; For example, the statement in C++: in Java: int u[8]; int u[]=new int[8]; declares the variable u as a one-dimensional integer array with a length of 9. As re-gards the entry u n in programs, we write u[n] .

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  eBook - ePub

  Composite Data Structures and Modularization

  Volume 2: Composite Data Structures and Modularization

  • Xingni Zhou, Qiguang Miao, Lei Feng(Authors)
  • 2020(Publication Date)
  • De Gruyter

    (Publisher)

  Figure 1.7 shows how to define an array, where a definition is constructed by a type identifier followed by an array name and multiple constants inside square brackets. Each constant indicates the number of variables in the corresponding dimension.

  Figure 1.7: Definition of arrays.

  In the figure above, the first row defines a one-dimensional integer array x with 100 variables. To compute the size of its memory space, we can obtain the size of its type using the sizeof operator and multiply it with the number of variables. The second row defines a two-dimensional character array with two rows and three columns. In other words, it has six variables in total. The array name is c.

  1.2.1.2  Reference of array elements

  C uses a special term for variables in an array: array elements. An array element is used in the same way as a single variable. To reference an array element, we use the array name suffixed by an index wrapped in square brackets.

  Think and discuss Do contents inside square brackets in an array definition and an element reference refer to the same thing?

  Discussion: The index of an array element is a numerical expression, which indicates the position of the element in an array; the object inside square brackets in an array definition has to be a constant, which indicates the number of elements in the corresponding dimension. It is worth noting that the number of elements must not be a variable. Like plain variables, arrays obtain memory space from the system during array definition. The size of the allocated space does not change during execution once the array is defined. Such a way of memory utilization and management is called static memory allocation. On the other hand, C also provides “dynamic memory allocation,” which will be introduced in examples in chapter “Functions”.

  Indices of array elements in C must start from 0. Accessing an array out of bound leads to a logic error, but it is not a syntax error.

  For example, the one-dimensional array x defined in Figure 1.8

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  eBook - ePub

  ANSI C Programming

  Learn ANSI C step by step

  • Yashavant Kanetkar(Author)
  • 2020(Publication Date)
  • BPB Publications

    (Publisher)

  Can we not refer to the same element using pointer notation, the way we did in one- dimensional arrays? Answer is yes. Only the procedure is slightly difficult to understand. So, read on…

  Pointers and 2-Dimensional Arrays

  The C language embodies an unusual but powerful capability—it can treat parts of arrays as arrays. More specifically, each row of a two-dimensional array can be thought of as a one-dimensional array. This is a very important fact if we wish to access array elements of a two-dimensional array using pointers.

  Thus, the declaration, int s[5][2];

  can be thought of as setting up an array of 5 elements, each of which is a one-dimensional array containing 2 integers. We refer to an element of a one-dimensional array using a single subscript. Similarly, if we can imagine s to be a one-dimensional array, then we can refer to its zeroth element as s[0] , the next element as s[1] and so on. More specifically, s[0] gives the address of the zeroth one-dimensional array, s[1] gives the address of the first one-dimensional array and so on. This fact can be demonstrated by the following program.

  And here is the output… Address of 0 th 1-D array = 65508 Address of 1 th 1-D array = 65512 Address of 2 th 1-D array = 65516 Address of 3 th 1-D array = 65520

  Let’s figure out how the program works. The compiler knows that s is an array containing 4 one-dimensional arrays, each containing 2 integers. Each one-dimensional array occupies 4 bytes (two bytes for each integer). These one-dimensional arrays are placed linearly (zeroth 1-D array followed by first 1-D array, etc.). Hence, each one-dimensional array starts 4 bytes further along than the last one, as can be seen in the memory map of the array shown in Figure 10.6 .

  Figure 10.6

  We know that the expressions s[0] and s[1] would yield the addresses of the zeroth and first one-dimensional array respectively. From Figure 10.6 these addresses turn out to be 65508 and 65512.

  Now, we have been able to reach each one-dimensional array. What remains is to be able to refer to individual elements of a one-dimensional array. Suppose we want to refer to the element s[2][1] using pointers. We know (from the above program) that s[2] would give the address 65516, the address of the second one-dimensional array. Obviously (65516 + 1) would give the address 65518. Or (s[2] + 1) would give the address 65518. And the value at this address can be obtained by using the value at address operator, saying *(s[2] + 1) . But, we have already studied while learning one-dimensional arrays that num[i] is same as*(num + i) . Similarly, *(s[2] + 1) is same as, *(*(s + 2) + 1)

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  A Textbook of Data Structures and Algorithms, Volume 1

  Mastering Linear Data Structures

  • G. A. Vijayalakshmi Pai(Author)
  • 2022(Publication Date)
  • Wiley-ISTE

    (Publisher)

  3 Arrays 3.1. Introduction In Chapter 1, an abstract data type (ADT) was defined to be a set of data objects and the fundamental operations that can be performed on this set. In this regard, an array is an ADT whose objects are a sequence of elements of the same type, and the two operations performed on it are store and retrieve. Thus, if a is an array, the operations can be represented as STORE (a, i, e) and RETRIEVE (a, i), where i is termed the index and e is the element that is to be stored in the array. These functions are equivalent to the programming language statements a[i ]:= e and a[i], where i is termed subscript and a is termed array variable name in programming language parlance. Arrays can be one-dimensional, two-dimensional, three-dimensional or in general multidimensional. Figure 3.1 illustrates a one-dimensional and two-dimensional array. It may be observed that while one-dimensional arrays are mathematically likened to vectors, two-dimensional arrays are likened to matrices. In this regard, two-dimensional arrays also have the terminologies of rows and columns associated with them. Figure 3.1. Examples of arrays 46 A Textbook of Data Structures and Algorithms 1 In Figure 3.1, A[1:5] refers to a one-dimensional array where 1 and 5 are referred to as the lower and upper indexes or the lower and upper bounds of the index range, respectively. Similarly, B[1:3, 1:2] refers to a two-dimensional array where 1, 3 and 1, 2 are the lower and upper indexes of the rows and columns, respectively. Additionally, each element of the array, namely, A[i] or B[i, j], resides in a memory location also called a cell. Here, the cell refers to a unit of memory and is machine dependent. 3.2. Array operations An array, when viewed as a data structure, supports only two operations, namely: (i) storage of values, that is, writing into an array (STORE (a, i, e)); (ii) retrieval of values, that is, reading from an array (RETRIEVE (a, i)).

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  Compact Data Structures

  A Practical Approach

  • Gonzalo Navarro(Author)
  • 2016(Publication Date)
  • Cambridge University Press

    (Publisher)

  CHAPTER 3 Arrays An array A[1, n] is a sequence of elements that can be read and written at arbitrary positions. That is, the array is an abstract data type that supports the operations: read(A, i ): returns A[i], for any 1 ≤ i ≤ n. write(A, i, x): sets A[i] ← x, for any 1 ≤ i ≤ n and any x. Unlike the classical array programming construct, we are interested in space- efficient array representations, which hopefully store only the useful bits of each num- ber A[i]. In some cases the array values are uniform and it is reasonable to use the same number of bits for all. In others, the numbers are very different and we prefer to allocate a variable number of bits for each. Example 3.1 If we are storing the number of days per month worked by employees, then 5 bits are sufficient, and usually necessary too. On the other hand, if we store the number of children of employees, although in principle the number is not bounded, 1–3 bits will be sufficient for most of them. It is not space-efficient to allocate the maximum number of bits for everyone. As seen in Chapter 2, variable-length elements also appear frequently as a result of compression, and compression will generally not work if we allocate the maximum number of bits to every element. In Chapter 2 we described ways to encode the variable- length elements so that the sequences can be decoded from the beginning. In this chap- ter we are more ambitious: to support read on arrays efficiently, we need to directly extract the bits corresponding to any arbitrary element. In this chapter we discuss how to store arrays in compact form, using ideally only the bits needed for each element, while providing efficient read operations. We will also provide efficient write operations on arrays of fixed-length cells. On variable-length cells, a write operation may change the length of the cell, which introduces other com- plications that will be dealt with later (in Chapter 12).

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