1 #include 
     
       2 #define    PI 3.14159 3 int main(void){ 4     float area, circum, radius; 5  6     printf("What is the radius of your pizza>\n"); 7     scanf("%f", &radius); 8     area = PI * radius *
     

radius; 9     circum = 2 * PI *radius;10     printf("Your pizza parameters are as follows:\n");11     printf("Circumference = %1.2f, area = %1.2f \n", circum, area);12     getchar();13     return 0;14 }

The #define statement can be used for character and string constants,too . The following example are valid:

1 #define BEEP '\a'2 #define TEE 'T'3 #define ESC '\033'4 #define OOPS "Now you have done it!" Remember: 1 It is a sensible C tradition to type constants in uppercase. 2 Don't make the common error when using the #define. 3 The const Modifier makes variables read-only ;you cannot alter the value of the variables. 4 C has a third way to create symbolic constants,and that is the enum.