3-0.cpp

Accelerated C++ 课后练习题 本人自己完成、可供参考

#include<algorithm>
#include<iomanip>
#include<ios>
#include<iostream>
#include<string>
#include<vector>
/*
using std::cin;
using std::sort;
using std::cout;				//来自原文的申明
using std::endl;				//这些申明为什么不可用??????

using std::setprecision;
using std::streamsize;
using std::string;
using std::vector;
*/
using namespace std;			//更改成这样就可以了

int main()
{
	cout<<"Please enter your first name: ";
	string name;
	cin>>name;
	cout<<"Hello, "<<name<<"!"<<endl;

	cout<<"Please enter your midterm and final exam grades: ";
	double midterm,final;
	cin>>midterm>>final;

	cout<<"Enter all your homework grades, "
		"followed by end-of-file: ";

	vector<double> homework;
	double x;
	while(cin>>x)
		homework.push_back(x);
	typedef vector<double>::size_type vec_sz;
	vec_sz size=homework.size();
	if(size==0)
	{
		cout<<endl<<"You must enter your name grades. "
			<<"please try again."<<endl;
		return 1;
	}
	
	sort(homework.begin(),homework.end());


	vec_sz mid=size/2;
	double median;
	median=(size%2==0)?(homework[mid]+homework[mid-1])/2
		:homework[mid];
	streamsize prec=cout.precision();
	cout<<"Your final grade is "<<setprecision(3)
	    <<0.2*midterm+0.4*final+0.4*median
		<<setprecision(prec)<<endl;



	return 0;
}