#include <iostream>
#include <iomanip> // for std::setprecision
 
int main() {
    // 반지름을 저장할 변수
    double radius;
    // 원주율
    const double pi = 3.14;
 
    // 사용자로부터 반지름 입력받기
    std::cout << "원의 반지름을 입력하세요: ";
    std::cin >> radius;
 
    // 원의 넓이 계산
    double area = pi * radius * radius;
 
    // 결과를 소수점 이하 둘째 자리에서 반올림하여 첫째 자리까지 출력
    std::cout << "원의 넓이는: " << std::fixed << std::setprecision(1) << area << std::endl;
 
    return 0;
}
 

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