C Tutorial/Data Type/const

Constants

<source lang="cpp">#include <stdio.h> main() {

 const int x = 20;
 const float PI = 3.14;
 printf("\nConstant values are %d and %.2f\n", x, PI);

}</source>

Constant values are 20 and 3.14

Constants and Variables with macro

<source lang="cpp">#include <stdio.h>

1. define SPEED 55

int main() {

     printf("SPEED %i.\n",SPEED);
     printf("SPEED+15 %i.\n",SPEED+15);
     printf(" %i MPH sign?\n",SPEED);
     return(0);

}</source>

SPEED 55.
      SPEED+15 70.
       55 MPH sign?

Define constant float value using const

<source lang="cpp">#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;

}</source>

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