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What are the constants with an example in C language?
Constant is also known as variable where once defined, the value never changes during the program execution. Thus, we can declare a variable as constant that refers to fixed values. It is also called as literals. Const keyword has to be used to define a constant.
Syntax
The syntax for constant that is used in C programming language is given below −
const type VariableName; (or) const type *VariableName;
Different types of constants
The different types of constants that are used in C programming language are as follows −
Integer constants − For example: 1,0,34,4567
Floating-point constants − For example: 0.0, 156.89, 23.456
Octal & Hexadecimal constants − For example: Hexadecimal: 0x2a, 0xaa .. and Octal: 033, 024,..
Character constants − For example: ‘a’, ‘B’, ‘x’
String constants − For example: “TutorialsPoint”
The types of constants are also What ised in the diagram below −
Example 1
Following is the C program for determining the value of a number −
#include<stdio.h> int main(){ const int number=45; int value; int data; printf("enter the data:"); scanf("%d",&data); value=number*data; printf("The value is: %d",value); return 0; }
Output
When the above program is executed, it produces the following result −
enter the data:20 The value of number is: 900
In the above program, if we try to change the value of a number which is declared as constant, it displays an error.
Example 2
Given below is the C program which gives an error, if we try to change the const value.
#include<stdio.h> int main(){ const int number=45; int data; printf("enter the data:"); scanf("%d",&data); number=number*data; printf("The value of number is: %d",number); return 0; }
Output
When the above program is executed, it produces the following result −
error