반올림, Math.round()

Math.round() 사용(반올림)

public class practice {
    public static void main(String[] args) {
        double pi = 3.141592;

        System.out.println(pi); // 3.141592
        System.out.println(pi * 1000); // 3141.592
        System.out.println(Math.round(pi * 1000)); // 3142

        System.out.println(Math.round(pi * 1000) / 1000); // 3
        System.out.println((double)Math.round(pi * 1000) / 1000); // 3.142
        System.out.println(Math.round(pi * 1000) / 1000.0); // 3.142
    }
}

 
int 사용(버림)

public class practice {
    public static void main(String[] args) {
        double pi = 3.141592;

        System.out.println(pi*1000); // 3141.592

        System.out.println((int)pi*1000); // 3000
        System.out.println((int)(pi*1000)); // 3141

        System.out.println((int)(pi*1000)/1000); // 3
        System.out.println((int)(pi*1000)/1000.0); // 3.141
    }
}