Java 代码

import java.util.Scanner;
import java.text.DecimalFormat;

public class Main
{
    public static void main(String[] args)
    {
        Scanner cin=new Scanner(System.in);
        double x=cin.nextDouble();
        double y=cin.nextDouble();
        double m=x/y;
        DecimalFormat df=new DecimalFormat("0.000");
        System.out.println(df.format(m)+" km/l");
    }
}

C++ 代码

#include<iostream>
#include<cstdio>
using namespace std;
int main()
{
    double x,y,m;
    cin>>x>>y;
    m=x/y;
    printf("%.3lf km/l\n",m);
    return 0;
}