Define Constant

Easy Preprocessor & Header Files

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Problem Statement

Write a C program using the `#define` preprocessor directive to define a constant value (e.g., PI = 3.14159) and compute the area of a circle given its radius.

Input Format

A single floating-point number representing radius R.

Output Format

Print the calculated area formatted to 4 decimal places.

Constraints

0.0 < R <= 100.0

Sample Input

5.0

Sample Output

78.5398

Explanation

Area = PI * R * R = 3.14159 * 25.0 = 78.53975 rounded to 78.5398.

Starter Code

#include <stdio.h>
#define PI 3.14159

int main() {
    float r;
    if (scanf("%f", &r) == 1) {
        // Write your code here
    }
    return 0;
}

Limits

Time Limit: 1s
Memory Limit: 256MB

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