Constant In C

Contant in C languauge

Constants normally refers to some fixed value, whose values can not be changed, these fixed values are called literals. Constants can be pf any of the basic data types like an integer constant, a floating constant. a character constant, or a string literals.

We can define constants in two ways :- 

1. Using #define preprocessor directives
2. Using a const keyword

Using #define preprocessor directive: This directive is used to declare an alias name for existing variable or any value. We can use this to declare a constant as shown below:

#define identifierName value

• identifierName: It is the name given to constant.
• value: This refers to any value assigned to identifierName.

Example:

#include<stdio.h>  
#define val 10  
#define floatVal 4.5  
#define charVal 'G'  
  
int main()  
{  
    printf("Integer Constant: %d\n",val);  
    printf("Floating point Constant: %.1f\n",floatVal);  
    printf("Character Constant: %c\n",charVal);  
      
    return 0;  
}  

Output :- 

Integer Constant: 10
Floating point Constant: 4.5
Character Constant: G

2. using a const keyword: Using const keyword to define constants is as simple as defining variables, the difference is you will have to precede the definition with a const keyword.

Example :- 

#include <stdio.h> 
  
int main() 
{ 
    // int constant 
    const int intVal = 10;  
  
    // Real constant 
    const float floatVal = 4.14; 
   
    // char constant  
    const char charVal = 'A';  
  
    // string constant 
    const char stringVal[10] = "ABC";  
      
    printf("Integer constant:%d \n", intVal ); 
    printf("Floating point constant: %.2f\n", floatVal ); 
    printf("Character constant: %c\n", charVal ); 
    printf("String constant: %s\n", stringVal); 
      
    return 0; 
} 

Output:

Integer constant: 10 
Floating point constant: 4.14
Character constant: A 
String constant: ABC 

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2. Basic Of C Language

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5. Basic Rules For Writting C Program

6. Keywords In C Language

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