Two ways of defining constants in C

*/ Defining constants by The "#define" Preprocessor */
#include <stdio.h>
#define LENGTH 10
#define WIDTH 5
#define NEWLINE '\n'
int main()
{
 int area;
 area = LENGTH * WIDTH;
 printf("value of area : %d", area);
 printf("%c", NEWLINE);
 return 0;
}

*/ Defining constants by The "const" Keyword */
#include <stdio.h>
int main()
{
 const int LENGTH = 10;
 const int WIDTH = 5;
 const char NEWLINE = '\n';
 int area;
 area = LENGTH * WIDTH;
 printf("value of area : %d", area);
 printf("%c", NEWLINE);
 return 0;
}