Modern C Programming Orhan Gazi Modern C Programming Including Standards C99, C11, C17, C23 Orhan Gazi Electrical and Electronics Engineering Ankara Medipol University Altındağ, Ankara, Türkiye (eBook) © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2024 This work is subject to the whole or part of the material is concerned, speciﬁcally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microﬁlms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a speciﬁc statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional afﬁliations. This Springer imprint is The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland Paper in this product is recyclable. C programing language was introduced in 1972. After its introduction, it became the most popular programming language in the world in short time. In every branch of science and engineering, developments occur in time, and every technology needs to update itself in time. Otherwise, it becomes old fashion in short time. Today, the popularity cycle of technologies is becoming shorter. C programming language was revised several times in the last several decades. The recent C standards are tabulated in Table 1. In Table 1, all the formal names start with the same expression IEC 9899, and after symbol “:,” the year of the standard is written, i.e., ISO/IEC 9899:1999 ISO/IEC 9899:2011 ISO/IEC 9899:2018 ISO/IEC 9899:2023 The year of C17 standard is 2018. Some people may use the informal name as C18. But in literature, it is seen that C17 was adopted by many authorities. Let’s brieﬂy give information about these standards. Table 1 C language standards since 1999 Informal name C99 C11 C17 C23 Introduction year Formal name ISO/IEC 9899:1999 ISO/IEC 9899:2011 ISO/IEC 9899:2018 ISO/IEC 9899:2023 File name N1256.pdf N1570.pdf N2310.pdf N3096.pdf (last draft) C99 Standard Formal name of this standard is ISO/IEC 9899:1999. This standard is published in 1999. The ﬁle name of this standard is N1256.pdf. Using internet search engines, all standard document can be found easily. C99 standard made major contribution to the C language; the standard introduced the header ﬁles complex number arithmetic floating-point environment formats for fixed-width integer types macros for Boolean data type fixed-width integer data types type-generic math With the introduction of these header ﬁles, it became much easier to perform complex mathematical calculations, and perform trigonometric operations. And ﬁxed-width integers were useful for efﬁcient use of the resources. New built-in data types introduced in C99 are long long, unsigned long long _Bool, _Complex, _Imaginary inline, restrict Variable length arrays were introduced in C99. Before C99, integer constants can be used for array sizes, and they must be deﬁned before the array declaration. In C99 standard, we can declare an array whose size is known at run time. That is, you can get the array size from the user at run time. In C99, the keyword static can be used inside the square brackets during array declaration, for example: void myFunc(int a[static 20]) // statements Before C99, single line comments, //. . ., are not accepted. C99 introduced single line comments. In addition, before C99, variable declarations must be done at the beginning of the code; however, with C99, variable declarations can be made in any place of the code. vii C11 Standard Formal name of this standard is ISO/IEC 9899:2011. The ﬁle name where the standard is published is N1570.pdf. Using internet search engines, it is possible to ﬁnd all the document standards easily. After C99 release, a major contribution to the C language is made by the C11 standard. The header ﬁles introduced in C11 standard are alignas and alignof macros atomic operations noreturn macro thread functions UTF-16 and UTF-32 encoding With C11, standard parallel processing became possible using built in thread functions, and it was possible to avoid the race problem occurring in parallel processing using the atomic data types. Thread and atomic libraries were the powerful contribution of C11 standard. The keywords added by C11 standard are _Alignas _Alignof _Atomic _Noreturn _Static_assert _Generic _Thread_local C17 Standard The standard C17 does not introduce new language features. In this standard, just some minor defects of the C11 standard are ﬁxed. C23 Standard The major contribution of C23 standard is the introduction of two new header ﬁles functions and macros for checked integer arithmetic functions and macros for bit manipulation These ﬁles are useful to use the hardware as efﬁcient as possible. In this book, starting from the most basic topics of C programming language, we cover new language features introduced in the standards. focuses on the representation of numbers in computer. This chapter is usually skipped in many C viii books. However, for a good understating of C programming, good knowledge of number representations in computer is needed. We advise the reader to study the ﬁrst chapter before processing with C programming topics. Chapters 2, 3, 4, 5, 6, 8, and 9 cover the common topics of all the standards. explains the pointers in C programming, and for good comprehension of this chapter, some knowledge about digital hardware fundamentals is needed. Complex numbers and ﬁxed bit length integers are covered in Chaps. 7 and 13. These concepts are introduced in C99 standard. In Chaps. 15 and 16, threads and atomic data types are explained. These concepts are introduced in standard C11 and they are also covered in C17 and C23. Macros, type qualiﬁers, storage classes, signals, enumerations included in all standards are covered in Chaps. 11, 12, and 14. This book can be adapted as a text or supplementary book for C programming for a one-semester course, or it can be read for personal development. I dedicate this book to my lovely brother Ilhan Gazi, and to those people who do something useful for humanity. Ankara, Turkiye Wednesday, August 2, 2023 Orhan Gazi Contents Representation of Numbers and Characters in Computer . . . . . . . . 1.1 Number Bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.1 Decimal Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.2 Binary Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.3 Octal Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.4 Hexadecimal Numbers . . . . . . . . . . . . . . . . . . . . . . 1.2 Conversion Between Bases . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.1 Binary to Decimal Conversion . . . . . . . . . . . . . . . . . 1.2.2 Binary to Octal Conversion . . . . . . . . . . . . . . . . . . . 1.2.3 Binary to Hexadecimal Conversion . . . . . . . . . . . . . 1.2.4 Decimal to Binary Conversion . . . . . . . . . . . . . . . . . 1.2.5 Octal to Binary Conversion . . . . . . . . . . . . . . . . . . . 1.2.6 Hexadecimal to Binary Conversion . . . . . . . . . . . . . 1.2.7 Hexadecimal to Decimal Conversion . . . . . . . . . . . . 1.3 Positive Integers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 Two’s Complement Form . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 Negative Integers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7 Memory Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.8 How Are the Integers Stored in Computer Memory, Big-Endian, and Little-Endian? . . . . . . . . . . . . . . . . . . . . . . . Data Types and Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 How to Start Writing a C Program? . . . . . . . . . . . . . . . . . . . . 2.2 Comments in C Programming . . . . . . . . . . . . . . . . . . . . . . . . 2.3 The First C Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 Variables and Data Types . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 Binary Number Representation in Modern C . . . . . . . . . . . . . . 2.6 sizeof Operator in C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 Unsigned Char Data Type . . . . . . . . . . . . . . . . . . . . . . . . . . .