C++ LANGUAGE DEFINING CONSTANTS PAGE 30

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C++ LANGUAGE DEFINING CONSTANTS

Defining Constants 


There are two simple ways in C++ to define constants: 

• Using #define preprocessor. 

• Using const keyword. 

The #define Preprocessor 

Following is the form to use #define preprocessor to define a constant: 

#define identifier value 

Following example explains it in detail: 

#include <iostream> 

using namespace std; 
 
#define LENGTH 10    
#define WIDTH  5 
#define NEWLINE '\n' 
 
int main() 
{ 
 
   int area;   
    
   area = LENGTH * WIDTH; 
   cout << area; 
   cout << NEWLINE; 
   return 0; 
} 
When the above code is compiled and executed, 
it produces the following result: 
50