Define macro: constant
/* Define macro */ #include <stdio.h> #define PI 3.14159f /* Definition of the symbol PI */ void main() { float radius = 0.0f; float diameter = 2.0f; float circumference = 0.0f; float area = 0.0f; radius = diameter/2.0f; circumference = 2.0f*PI*radius; area = PI*radius*radius; printf("\nThe circumference is %.2f", circumference); printf("\nThe area is %.2f", area); }