C constant

In the previous article, I introducedVariables in C.

In this article, I want to tell you all about C constants.

The declaration of a constant is similar to the declaration of a variable, except that the constant is preceded byconstKeyword, then you always need to specify a value.

like this:

const int age = 37;

This is perfectly valid C language, although constants are usually declared in uppercase as follows:

const int AGE = 37;

This is just a convention, but it can be a great help when reading or writing this bookCProgram because it improves readability. Uppercase names indicate constants, lowercase names indicate variables.

Constant names follow the same variable name rules: they can contain any uppercase or lowercase letters, they can contain numbers and underscore characters, but they cannot start with a number.AGEwithAge10Is a valid variable name,1AGEIt's not.

Another way to define constants is to use the following syntax:

#define AGE 37

In this case, you don’t need to add types, and you don’t need to=The equal sign, and then omit the semicolon at the end.

The C compiler will infer the type based on the specified value at compile time.

More clang tutorials:

• Introduction to C programming language
• C variables and types
• C constant
• C operator
• C conditional
• How to use loops in C
• Introduction to C arrays
• How to determine the length of an array in C
• Introduction to C strings
• How to find the length of a string in C
• C pointer introduction
• Iterate over the array in C
• Boolean in C
• Introduction to C functions
• How to use NULL in C
• Basic I/O concepts in C language
• Double quotes and single quotes in C
• How to return a string from a C function
• How to solve the implicit declaration library function warning in C language
• How to check character value in C
• How to use `printf()` to print percent characters in C language
• C conversion specifiers and modifiers
• How to access command line parameters in C
• Range of variables in C
• Can functions be nested in C?
• Static variables in C
• C global variables
• Typedef keyword in C language
• C enumeration type
• C structure
• C header file
• C preprocessor