C language tutorial

"C Language Tutorial" C language is a general-purpose, procedural-oriented computer programming language. In 1972, Dennis Ritchie designed and developed the C language at Bell Telephone Laboratories in order to port and develop the UNIX operating system. C language is a widely used computer language that is as popular as the Java programming language and both are widely used among modern software programmers.

C language is a process-oriented, abstract, general-purpose programming language that is widely used in low-level development. C language can compile and process low-level memory in a simple way.

C language is a high-efficiency programming language that only generates a small amount of machine language and can run without any operating environment support.

Although the C language provides many low-level processing functions, it still maintains cross-platform characteristics. C language programs written in a standard specification can be used in tasks such as embedded processors and supercomputers. The platform is compiled on many computer platforms.

Tips: Before starting this tutorial, you need to have a basic understanding of computer programming terminology. Have a basic understanding of any programming language, such as PHP, Python, etc., which will help you understand C language programming concepts and help speed up your learning progress .

C language is a process-oriented computer programming language, which is different from object-oriented programming languages ​​such as C and Java. The design goal of the C language is to provide a programming language that can be easily compiled, handle low-level memory, generate only a small amount of machine code, and can run without any runtime environment support.

Let’s experience the first C program!

The first C program

#include <stdio.h>

int main()
{
   /* 我的第一个 C 程序 */
   printf("Hello, World! \n");
   
   return 0;
}

C language describes problems faster than assembly language, has less workload, is more readable, easier to debug, modify and transplant, and the code quality is equivalent to assembly language.

Tips: Our C language tutorial will help you learn the C programming language and its applications step by step. If you have any questions, please go to the PHP Chinese website C language Ask your questions in the community and enthusiastic netizens will answer them for you.

Main features of C language

(1) Concise language

C language contains only 9 kinds of various control statements, and the keywords are also There are only 32. The writing requirements of the program are not strict and mostly use lowercase letters. Many unnecessary parts have been streamlined. In fact, the composition of statements is rarely related to hardware, and the C language itself does not provide hardware-related input, output, file management and other functions. If such functions are needed, programming needs to be done with various libraries supported by the compilation system. , so the C language has a very simple compilation system.

(2) Structured control statements

C language is a structured language, and the control statements provided have structured features, such as for statements, if⋯else statements and switch Statements etc. It can be used to implement logical control of functions and facilitate process-oriented programming.

(3) Rich data types

C language contains a wide range of data types, including not only traditional character types, integer types, floating point types, array types and other data types, but also Among the data types that other programming languages ​​do not have, pointer type data is the most flexible to use, and various data structures can be calculated through programming.

(4) Rich operators

C language contains 34 operators. It treats assignments, parentheses, etc. as operators to operate, making the expression types and operations of C programs The character types are very rich.

(5) Direct manipulation of physical addresses

C language allows direct reading and writing of hardware memory addresses, so that the main functions of assembly language can be realized and the hardware can be directly operated. C language not only has the good characteristics of high-level languages, but also contains many advantages of low-level languages, so it is widely used in the field of system software programming.

(6) The code has good portability

The c language is a process-oriented programming language. Users only need to focus on the problem being solved without spending too much time. Focus on understanding the relevant hardware, and for different hardware environments, the code when using C language to implement the same function is basically the same, and the transplant can be completed without or only a small amount of changes. This means that for a computer written C programs can be easily run on another computer, thus greatly reducing the work intensity of program transplantation.

(7) High-quality target code that can be generated, and programs with high execution efficiency

Compared with other high-level languages, C language can generate high-quality and high-efficiency target code, so it is usually It is suitable for writing embedded system programs that require high code quality and execution efficiency.

Unique features of C language

• First, universality. The size of the operation range of C language directly determines its advantages and disadvantages. The C language contains 34 operators, so the range of operations exceeds that of many other languages. In addition, the expression forms of its operation results are also very rich. In addition, the C language includes various data structure forms such as character type and pointer type. Therefore, it can also handle larger data structure operations.

• Second, simplicity. 9 types of control statements and 32 KEYWORDS are the basic features of C language, which make it widely applicable in computer application writing. It can not only be suitable for the operations of programmers and improve their work efficiency, but also support advanced Programming avoids the tediousness of language switching.

• Third, the structure is perfect. C language is a structured language that can implement modular applications by forming module units. It has significant advantages in system description. At the same time, this feature also enables it to adapt to a variety of different programming requirements, and High execution efficiency.

Disadvantages

• The shortcomings of C language are mainly reflected in the encapsulation of data, which makes C have a lot of advantages in data security. Big flaw, this is also a big difference between C and C.

• The syntax restrictions of C language are not too strict, and the type constraints of variables are not strict, which affects the security of the program. There is no check for out-of-bounds array subscripts, etc. From an application perspective, C language is more difficult to master than other high-level languages. In other words, people who use C language are required to be more proficient in programming.

Content covered by this C language tutorial manual

This tutorial covers comprehensive knowledge of C language, including C language syntax, types, variables, functions, and arrays , a detailed introduction to scope, sorting algorithm, C standard library, etc.

Tips: Each chapter of this tutorial contains many C examples. You can directly click the "Run Example" button to view the results online. These examples will help you better understand and use C language.