In C language, the constant type qualifier is used to specify that a variable is a constant, that is, its value cannot be modified after initialization. The constant type qualifier can be implemented by placing the keyword const before the variable declaration. For example: const int x = 5; In the above example, the variable x is declared as a constant, its value is initialized to 5, and cannot be modified in subsequent code. The use of constant type qualifiers can improve the readability and maintainability of code because it clearly indicates the purpose and limitations of the variable

Type qualifiers add special attributes to existing datatypes in C programming language.

There are three type qualifiers in C language and constant type qualifier is explained below −

Const

There are three types of constants, which are as follows −

• Literal constants

• Defined constants

• Memory constants

Literal constants − These are the unnamed constants that are used to specify data.

For example,

a=b+7 //Here ‘7’ is literal constant.

Defined constants − These constants use the preprocessor command 'define" with

#For example, #define PI 3.1415

Memory constants − These constants use 'C' qualifier 'const', which indicates that the data cannot be changed.

The syntax is as follows −

const type identifier = value

For example,

const float pi = 3.1415

As you can see, it just gives a literal name.

Example

The following is the C program for constant type qualifier:

#include<stdio.h>
#define PI 3.1415
main ( ){
   const float cpi = 3.14
   printf ("literal constant = %f",3.14);
   printf ("defined constant = %f", PI);
   printf ("memory constant = %f",cpi);
}

Output

When the above program is When executed, it produces the following result −

literal constant = 3.14
defined constant = 3.1415
memory constant = 3.14

The above is the detailed content of In C language, the constant type qualifier is used to specify that a variable is a constant, that is, its value cannot be modified after initialization. The constant type qualifier can be implemented by placing the keyword const before the variable declaration. For example: const int x = 5; In the above example, the variable x is declared as a constant, its value is initialized to 5, and cannot be modified in subsequent code. The use of constant type qualifiers can improve the readability and maintainability of code because it clearly indicates the purpose and limitations of the variable. For more information, please follow other related articles on the PHP Chinese website!