In C, constants are fixed values that don’t change during program execution — perfect for storing things like PI, max sizes, or fixed config values. ??

? Types of Constants in C

? 1. Literal Constants

These are actual fixed values written directly in code:

c
float pi = 3.14;     // Float constantchar grade = 'A';    // Character constant

? 2. #define Constants (Macro)

Use the preprocessor to define constants:

c
#define PI 3.14159const int maxScore = 100;const float taxRate = 0.18;

• Cannot be changed later in code

• Has type checking at compile time

c
maxScore = 200; // ? Error: assignment of read-only variable

? Difference Between #define and const

? Constants with Arrays

c
const int SIZE = 5;int numbers[SIZE]; // Valid

? Example with Constants

c
#include #define PI 3.14int main() {    const int radius = 5;    float area = PI * radius * radius;    printf("Area: %.2f\n", area);    return 0;}