The basic units of C language and their functions

C language is a programming language widely used in system programming and application development. In the C language, there are some basic units that programmers often come into contact with when writing programs. Mastering these basic units is very important for mastering the C language. This article will introduce the basic units in C language and their functions in detail, and provide specific code examples to help readers better understand.

1. Keywords (Keywords):
   Keywords in C language are defined in advance by the compiler, have special meanings, and cannot be used by programmers as Identifier usage. For example:int,char,if,for, etc. The following is a simple code example:

   #include  int main() { int a = 10; char b = 'A'; if (a > 5) { printf("a大于5 "); } for (int i = 0; i < 5; i++) { printf("i的值：%d ", i); } return 0; }

2. Identifiers:
   Identifiers are defined by programmers to identify variables, Functions, arrays, etc. Identifiers can be composed of letters, numbers, and underscores, but must begin with a letter or an underscore. The following is an example:

   #include  int main() { int num = 10; printf("num的值：%d ", num); return 0; }

3. Data Types:
   There are some basic data types in C language, such as integer and character , floating point type, etc. The following is an example:

   #include  int main() { int integerNum = 10; char charVar = 'A'; float floatNum = 3.14; printf("整型变量：%d ", integerNum); printf("字符型变量：%c ", charVar); printf("浮点型变量：%f ", floatNum); return 0; }

4. Operators:
   There are various operators in C language, such as assignment operators and arithmetic operators , logical operators, etc. The following is an example:

   #include  int main() { int a = 10; int b = 20; int sum = a + b; int product = a * b; printf("和：%d ", sum); printf("积：%d ", product); return 0; }

5. Control Flow Statements:
   Control flow statements in C language include if statements, for loops, while loops, etc., are used to control the execution flow of the program. The following is an example:

   #include  int main() { int num = 10; if (num > 5) { printf("num大于5 "); } else { printf("num小于等于5 "); } for (int i = 0; i < 5; i++) { printf("i的值：%d ", i); } return 0; }

By learning the basic units and their functions in C language, it can help readers better understand the core concepts of C language and improve the efficiency and quality of program writing. . I hope the content of this article will be helpful to readers.

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