Define constant float value using const : const « Data Type « C Tutorial

1. C Tutorial
2. Data Type
3. const

#include <stdio.h>

int main(void)
{
  float diameter = 0.0f;            
  float radius = 0.0f;              
  const float Pi = 3.14159f;        

  printf("Input the diameter of the table:");
  scanf("%f", &diameter);
  radius = diameter/2.0f;
  printf("\nThe circumference is %.2f", 2.0f*Pi*radius);
  printf("\nThe area is %.2f", Pi*radius*radius);
  return 0;
}

Input the diameter of the table:123
     
     The circumference is 386.42
     The area is 11882.28