如果原来的小数位数少于
如果原来的小数位数多于
#include<iostream> #include<iomanip> using namespace std; int main(){ double a; cin >> a; cout << fixed << setprecision(3) << a << endl; return 0; }
using System; public class Program { public static void Main() { //获取输入 string line = System.Console.ReadLine (); //查找小数点位置 int index = line.IndexOf('.'); if (index == -1 ) { //没找到,是整数,要补三个0 line += ".000"; } else if (line.Length - 1 - index < 3) { //小数位数少于 3 ,需要补充 0 int n = 3 - (line.Length - 1 - index); //补的数量 for (int i = 0; i < n; i++) line += "0"; } else if (line.Length - 1 - index > 3) { //小数位数大于 3 ,需要四舍五入 double number = double.Parse(line); number = Math.Round(number, 3); line = number.ToString(); } System.Console.WriteLine(line); } }
double d = in.nextDouble(); System.out.println(String.format("%.3f",d));
import java.text.DecimalFormat; import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner in = new Scanner(System.in); float n = in.nextFloat(); // 使用DecimalFormat 格式化小数,保留3位小数 DecimalFormat df = new DecimalFormat("0.000"); String s = df.format(n); System.out.println(s); in.close(); } }