C Array of Structures

7 Key excerpts on "C Array of Structures"

• 

  eBook - ePub

  Matlab

  A Practical Introduction to Programming and Problem Solving

  • Dorothy C. Attaway, Stormy Attaway(Authors)
  • 2009(Publication Date)
  • Butterworth-Heinemann

    (Publisher)

  Chapter 7

  Data Structures

  Cell Arrays and Structures

  Contents

  7.1 Cell Arrays 7.2 Structures

  Key Words

  data structure structure field database record cell array vector of structures nested structure

  Data structures are variables that store more than one value. In order for it to make sense to store more than one value in a variable, the values should somehow be logically related. There are many different kinds of data structures. We have already been working with one kind, arrays (e.g., vectors and matrices). An array is a data structure in which all the values are logically related in that they are of the same type, and represent in some sense the same thing. So far, that has been true for the vectors and matrices that we have used.

  A cell array is a kind of data structure that stores values of different types. Cell arrays can be vectors or matrices; the different values are stored in the elements of the array. One very common use of a cell array is to store strings of different lengths.

  Structures are data structures that group together values that are logically related, but are not the same thing and not necessarily the same type. The different values are stored in separate fields of the structure.

  One use of structures is to set up a database of information. For example, for a class a professor might want to store information for every student in the class: the student’s name, university ID number, grades on all assignments and quizzes, and so on. In many programming languages and database programs, the terminology is that within a database file, there would be one record of information for each student; each separate piece of information (name, quiz 1 score, etc.) would be called a field of the record. In the MATLAB® software these records are called structs .

  7.1 Cell Arrays

  One type of data structure that MATLAB has but is not found in many programming languages is a cell array

  Sign up to read

  Learn more about book
• 

  No longer available |Learn more

  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.

  Sign up to read

  Learn more about book
• 

  eBook - ePub

  C++ Programming

  • Yuan Dong, Fang Yang, Li Zheng(Authors)
  • 2019(Publication Date)
  • De Gruyter

    (Publisher)

  6Arrays, Pointers, and Strings

  After studying the concepts and applications of basic control structures, functions, and classes of C++, many problems can be described and solved. However, for large scales of data, especially when they are mutually correlated or are similar and correlated data, how to present and organize them efficiently remains a problem. The array type in C++ provides an effective way to organize objects of the same type.

  An important characteristic, which C++ inherits from C, is that we can directly use an address to access memory, and the pointer variable is an important data type for realizing this feature. Using pointers, we can conveniently process large amounts of data continuously stored in memory, achieve massive data sharing between functions at a comparatively low cost, and easily realize dynamic memory allocations.

  Using character arrays to make up the deficiency of string variables is an effective method inherited from C. However, from the object-oriented and security perspectives, strings represented by character arrays have deficiencies. Therefore, the standard class library of C++ provides the string class, which is a good example of expanding data types based on the class library.

  In this chapter, we will introduce the array type, pointer type, dynamic memory allocation, and how to store and process string data.

  6.1Arrays

  To understand the function of an array, please consider this problem: how does one store and process a series of n integers in a program? If n is small, for example, n is 3, we can easily declare three variables of the int type. If n is 10,000, then we need to declare 10,000 variables of int type to represent these 10,000 numbers by int

  Sign up to read

  Learn more about book
• 

  eBook - ePub

  Learn C Programming from Scratch

  A step-by-step methodology with problem solving approach (English Edition)

  • Mohammad Saleem Mir(Author)
  • 2024(Publication Date)
  • BPB Publications

    (Publisher)

  HAPTER 5Arrays Introduction

  In this chapter, we will explore various topics related to arrays, string manipulation, and matrices in the context of programming. Arrays, which are one-dimensional structures, allow us to store and manipulate a collection of elements. We will learn how to perform operations on arrays, such as accessing elements and modifying their values. Additionally, we will delve into string manipulation, understanding how to work with strings effectively. Furthermore, we will delve into matrices and explore how to pass a two-dimensional matrix to a function.

  Structure In this chapter, we will cover the following topics:

  • Arrays (One-dimensional array)
  • Array manipulation
  • String manipulation
  • Matrices
  • Passing 2-D matrix to a function

  Objectives

  The objective of this chapter is to provide a comprehensive understanding of arrays, string manipulation, and matrices. By the end of this chapter, you will be equipped with the knowledge and skills necessary to manipulate arrays effectively, perform string operations efficiently, and work with matrices in programming. Through practical examples and explanations, we aim to enable you to apply these concepts in your coding projects.

  Arrays: One-dimensional array

  In the C programming language, arrays are a fundamental type of data structure. They offer a practical and effective approach to handling and storing identical data items. Understanding arrays is crucial for creating effective and reliable software, whether you are an expert programmer or a newbie learning C. We may store a fixed-size collection of identical-type objects using the C data structure called an array. Arrays can group related data objects associated with a single name. Arrays allow for the contiguous (one after the other) storage of a fixed-size sequential collection of objects of the same kind. However, it is sometimes more helpful to conceive an array as a group of variables of identical type. Since we assign a name to all the elements of an array, it is imperative to identify the individual elements of an array uniquely. To access individual elements of an array, we use a unique integer called index,

  Sign up to read

  Learn more about book
• 

  eBook - ePub

  Ivor Horton's Beginning Visual C++ 2008

  • Ivor Horton(Author)
  • 2011(Publication Date)
  • Wrox

    (Publisher)

  tax , and so on. Of course, you would also need some means of picking out a particular employee from the whole bunch, together with the data from the generic variables associated with them. This kind of requirement arises with any collection of like entities that you want to handle in your program, whether they're baseball players or battleships. Naturally, C++ provides you with a way to deal with this.

  Arrays

  The basis for the solution to all of these problems is provided by the array in ISO/ANSI C++. An array is simply a number of memory locations called array elements or simply elements , each of which can store an item of data of the same given data type and which are all referenced through the same variable name. The employee names in a payroll program could be stored in one array, the pay for each employee in another, and the tax due for each employee could be stored in a third array.

  Individual items in an array are specified by an index value which is simply an integer representing the sequence number of the elements in the array, the first having the sequence number 0 , the second 1 , and so on. You can also envisage the index value of an array element as being an offset from the first element in an array. The first element has an offset of 0 and therefore an index of 0 , and an index value of 3 will refer to the fourth element of an array. For the payroll, you could arrange the arrays so that if an employee's name was stored in the employeeName array at a given index value, then the arrays pay and tax would store the associated data on pay and tax for the same employee in the array positions referenced by the same index value.

  The basic structure of an array is illustrated in Figure 4-1 .

  Figure 4-1

  Figure 4-1 shows an array. The name height has six elements, each storing a different value. These might be the heights of the members of a family, for instance, recorded to the nearest inch. Because there are six elements, the index values run from 0 through 5 . To refer to a particular element, you write the array name, followed by the index value of the particular element between square brackets. The third element is referred to as height[2]

  Sign up to read

  Learn more about book
• 

  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)

  We can use a for loop to process grades for a single student and use another one to calculate average grades for all of them. The algorithm and code implementation will be given in the section of two-dimensional arrays.

  1.1.2  Representation of data of the same type

  The discussion earlier showed that a new mechanism is necessary to handle data of the same type. With respect to data representation and processing, arrays are a data structure that regularly expresses data so that they are processed regularly.

  Since arrays are collections of variables whose names have a pattern, they are supposed to have features of variables. Figure 1.6 compares arrays with plain variables.

  Figure 1.6: Comparison of a group of variables with a single variable.

  During the definition of a plain variable, the system allocates memory according to its type specified by programmers. The definition of an array consists of type, name and, in particular, the number of variables in the array.

  There are multiple variable values in an array, so they should be stored in multiple storage units, whose sizes depend on types of the variables. The size of a storage unit is measured in bytes and can be computed using the sizeof operator.

  Besides, a referencing method of the address of a storage unit is necessary so that programmers can inspect the unit. We can infer from the examples earlier that the referencing method of variable values in an array is to use the array name with an index. Moreover, we should be able to initialize an array since we can do the same with plain variables. Hence, a corresponding syntax is necessary.

  1.2  Storage of arrays

  There are four issues related to array storage, namely definition, initialization, memory allocation, and memory inspection.

  1.2.1  Definition of arrays

  1.2.1.1  Definition of arrays

  An array is a collection of data of the same type. Figure 1.7

  Sign up to read

  Learn more about book
• 

  eBook - ePub

  C Programming

  Learn to Code

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

    (Publisher)

  10 Arrays and Strings

  DOI: 10.1201/9781003188254-10

  10.1 Introduction

  Many times, we come across a situation where we use a set of data rather than a single datum. For example, assume that you are an instructor and you teach C programming. You want to store the marks of your students and later perform different types of operations on them, such as finding the top performer or knowing how many students secure less than 50 marks. In that case usage of a single variable is not enough: you need multiple variables to store the data of your students. Again, if you use many variables in your program then remembering those variable names will become difficult. So, the solution is the array – a concept provided by C that handles large numbers of items simultaneously.

  In our day-to-day life we also came across situations where we need to group items and keep them in a sequential manner for easy access. For example, Figure 10.1 shows a toy train built to store painting items such as watercolors, sketch pens, brushes, pencils, and oil pastels. We name this train the Painter’s Train. We number the boxes from 1 to 5 and store many items in them. The concept of arranging similar data and calling them using a common name is sometimes known as an array of items.

  Figure 10.1 Introducing the concept of an array.

  An array is a series of elements of the same type, placed in contiguous memory locations that can be individually referenced by adding an index number to each location. Other definitions are:

  • An array is a single programming variable with multiple "compartments." Each compartment can hold a value.
  • A collection of data items, all of the same type, in which the position of each item is uniquely designated by a discrete type.

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

  Sign up to read

  Learn more about book