/************************************
备注：
************************************/
#include <iostream>
#include <cstdio>
#include <iomanip>
#include <cmath>
#include <algorithm>
#include <cstring>
#include <string>
#include <stack>
#include <queue>
#include <bits/stdc++.h>
#define LL long long
using namespace std;
const int INF = 0x3f3f3f3f;
const int N = 1e5 + 10;
double n;
int main()
{
	cin >> n;
	cout << fixed << setprecision(3) << n << endl;
	return 0;
}

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
const int N=1e7+10;
const int INF=0x3f3f3f3f;
int main()
{
	float a;
	cin>>a;
	cout<<fixed<<setprecision(3)<<a;
}

#include <iostream>
using namespace std;
int main() 
{
    double n;
    cin >> n;
    printf ("%.3f",n);
    return 0;
}

#include <bits/stdc++.h>

using namespace std;

int main(void)
{
    float a;

    cin >> a;

    cout << fixed << setprecision(3) << a;

    return 0;
}

这道题要多练😕

#include <iostream> #include <algorithm> #include <cstdio> #include <cstring> #include <string> #include <iomanip> #includejf #includedkjfsj #include<；；； #include #include using namespe std; #define long long LL const int N = 1e6+6; const int INF = 0jbjb设 int maisasa int n; cin >> n; cout << n / 3600 << endl; cout << (n - 3600 * (n / 3600)) / 60 << endl; cout << n % 60; return 0; ewsafasad dsdssfs }

#include <iostream>
using namespace std;
int main(){
	double a;
	scanf("%lf",&a);
	printf("%.3f",a);
	return 0;
}

#include<bits/stdc++.h>
#include <queue>
#include <math.h>
#include <stack>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <iomanip>
#include <string.h>
#include <algorithm>
using namespace std;
#define LL long long
const int N = 1e5 + 10;
const int INF = 0x3f3f3f3f;
int main()
{
    float n;
	scanf("%f",&n);
	printf("%.3f",n);
	return 0;		
}

#include<stdio.h> #include<iostream> #include<iomanip> using namespace std; int main() { double a; cin>>a; cout<<fixed<<setprecision(3)<<a<<endl; }

#include<iostream> #include<iomanip> using namespace std; int main(){ double a; cin >> a; cout << fixed << setprecision(3) << 1.0* a << endl; }

n = eval(input()) print("%.3f" % n)