> //============================================================================
> // Name        : main1607.cpp
> // Author      : 
> // Version     :
> // Copyright   : Your copyright notice
> // Description : Hello World in C++, Ansi-style
> //============================================================================
> 
> #include <iostream>
> #include <iomanip>
> #include <cmath>
> #include <stdio.h>
> using namespace std;
> 
> int main() {
> 	cout << "Cards  Overhang" << endl;
> 	int num;
> 	double ress[100000] = {0};
> 	int max = 0;
> 	while(cin >> num){
> 		double res = 0;
> 
> 		if(num > max){
> 			for(int i = max+1; i <= num; i++){
> 				ress[i] = ress[i-1] + 1.0/2/i;
> 			}
> 
> 			max = num;
> 
> 		}
> 		res = ress[num];
> 		int log = (int)log10(num * 1.0);
> 		for(int i = 0; i < 4 - log; i++){
> 			cout << " ";
> 		}
> 		cout << num;
> 		int spaces;
> 		if(res < 10) spaces = 5;
> 		else{
> 			spaces = 5 - (int)log10(res);
> 		}
> 		for(int i = 0; i < spaces; i++){
> 			cout << " ";
> 		}
> 		//cout << setprecision(3) << res << endl;
> 		printf("%.3lf\n", res);
> 	}
> 	//cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!!
> 	return 0;
> }
C++的setprecision不能乱用。。。好几次都栽在这个上面！