/* 这题其实不难，而且很贴近生活啊！等ACM题刷累了的时候，不妨把这个代码再多加些功能，写成一个小小的项目试试，我觉得会挺有意义 体现了的知识点： 为了避免浮点数的误差，一般在按小数点输入之前，要先将它和一个较小的数EPS(通常用1e-5)相加 打脸了...WA了将近一天，各种调试和找错，整整找了一天，没错，就是整整一天，不是上学的一天，是暑假的一整天，什么都不做专门调这道题的那种一天，好几次都崩溃到想放掉这道题...想着，WA就WA吧，反正真正比赛的时候，应该不会出这种题目 (这脸打得也太响了，我本来还想着，这道题看思路似乎挺简单，要不就不做了，先自学些数据结构等别的ACM题，结果...太轻视这题了啊！~) 但是想了想，不能这样啊，凡事只有0次和无数次的区别...如果我这次因为一直WA就放弃了，下次就可以因为这个数据结构/算法没学过，这道题太难，这道题一直没思路又没题解根本做不出...等等各种其他的理由放弃掉别的题。要放弃可以有很多理由~可是既然给自己划定了某个目标，就不要畏难，死磕也要磕到底，哪怕是付出再多时间，也一定要磕下来...战线可以拉长，不求在最近就弄明白，可是绝对不能在心里告诉自己：我不管了，太难了，这道题我就是做不出来了... 嗯，对自己还是不能放太多水，平时放的水，最后都会在WA时，变成自己深沉的泪水，hhh~ */
/* 版本1 这个题目其实挺好理解，我就不解释我的代码了，来讲讲我究竟是怎么WA的吧！ UVA的输出数据里面，应该有格式或者中西文标点的错误，因为我直接把UVA里面的这句输出复制下来 "Showing the ranklist hurts students’ self-esteem. Don’t do that." 提交代码的时候，就是WA 而我自己敲了这句以后，就只是改了这句，改为 "Showing the ranklist hurts students' self-esteem. Don't do that." 就AC了...惊不惊喜，意不意外，我会说，没想到还有这个天坑吗！ T^T...做这道题一定要注意注意再小心，至少这句话，不要直接从UVA的样例输出里面复制 (我会说复制，本来就是为了避免出现，中西文标点等看不出差别的问题，UVA的数据居然还这样坑我，真是天坑啊！卒~) 吐槽完毕，上代码...可以说是很艰难的AC了...唉 (对了，最终真正找到这个bug，还要多亏了命令行的神操作..下次专门写一篇博文讲下，我究竟是怎么发现，错误居然在这里的...最关键的突破点，是因为利用了命令行的txt比较功能) 话说，当时没想到还真的有这个操作，抱着试试的心态随手一搜，居然真的有...搜索引擎可真是个好东西啊!hhhhhhh....(大家多多百度谷歌吧，真的很多时候会有意外的收获呢！) 从此以后，我觉得我就可以借助重定向和这个比较功能，很方便地加各种输出语句来调试了...ohyeah!!~ 不知道什么时候能来填(如何利用命令行发现隐藏很深的WA原因)这个坑，就先把这个命令行神操作的网址放着好了 https://jingyan.baidu.com/article/19020a0a1dd04a529c284272.html */
#include <iostream>
#include <iomanip>
#include <string>
#include <cstring>
#include <algorithm>
#include <cstdio>
//#define debug
using namespace std;
const int maxn = 1e5;
const double EPS = 1e-5;
int n = 0;
int CID, _score[4], sum;
string SID, name, s;
const string course[] = {"Chinese", "Mathematics", "English", "Programming"};
const string words[] = {"Number of students who failed all subjects: ", "Number of students who passed 1 or more subjects: ", "Number of students who passed 2 or more subjects: ", "Number of students who passed 3 or more subjects: ", "Number of students who passed all subjects: "};
struct student
{
int CID, score[5]; // Chinese, Math, English, Programming, total
bool del;
double average;
string name, SID;
}stu[maxn];
void Print_Menu()
{
cout << "Welcome to Student Performance Management System (SPMS)." << endl << endl << "1 - Add" << endl << "2 - Remove" << endl << "3 - Query" << endl << "4 - Show ranking" << endl << "5 - Show Statistics" << endl << "0 - Exit" << endl << endl;
}
int valid() // 检查是否合法，如果输入的SID已经输入过了，则该输入不合法，因而不处理该输入
{
for (int i = 0; i < n; i++)
if (!stu[i].del)
if (stu[i].SID == SID)
return 0;
return 1;
}
int Rank (int k)
{
int cnt = 0;
for (int i = 0; i < n; i++)
{
if ( !stu[i].del && stu[i].score[4] > stu[k].score[4] ) cnt++;
}
return cnt + 1;
}
void Add()
{
while (1)
{
sum = 0;
cout << "Please enter the SID, CID, name and four scores. Enter 0 to finish." << endl;
cin >> SID;
if (SID == "0") return;
cin >> CID >> name;
for (int i = 0; i < 4; i++)
{
cin >> _score[i];
sum += _score[i];
}
if (!valid()) cout << "Duplicated SID." << endl;
else
{
stu[n].SID = SID; stu[n].CID = CID; stu[n].name = name;
for (int i = 0; i < 4; i++) stu[n].score[i] = _score[i];
stu[n].score[4] = sum;
stu[n].average = sum * 1.0 / 4 + EPS;
stu[n].del = false;
n++;
}
}
}
void Remove()
{
while (1)
{
cout << "Please enter SID or name. Enter 0 to finish." << endl;
cin >> s;
if (s == "0") break;
int cnt = 0;
for (int i = 0; i < n; i++)
{
if ( !stu[i].del && (stu[i].SID == s || stu[i].name == s) )
{
stu[i].del = true;
++cnt;
}
}
cout << cnt << " student(s) removed." << endl;
}
}
void Query()
{
while (1)
{
cout << "Please enter SID or name. Enter 0 to finish." << endl;
cin >> s;
if (s == "0") return;
for (int i = 0; i < n; i++)
{
char c = ' ';
if ( !stu[i].del && (stu[i].SID == s || stu[i].name == s) )
{
cout << Rank(i) << c << stu[i].SID << c << stu[i].CID << c << stu[i].name << c;
for (int j = 0; j < 5; j++) cout << stu[i].score[j] << c;
cout << fixed << setprecision(2) << stu[i].average << endl;
}
}
}
}
void Statistics()
{
cout << "Please enter class ID, 0 for the whole statistics." << endl;
int cid, i, j, passed, failed, total, cnt, cnt1;
cin >> cid;
int p[5]; // p[i]记录通过了i门课程的学生
char c;// c == ' '
memset(p, 0, sizeof(p)); // 每次调用都要清空p，p[i]代表了当前指定的范围的学生中,有p[i]或以上的同学通过了该课程
if (!cid) //cid == 0, 0 for the whole statistics，枚举所有学生，不论其班级是什么
{
for (int i = 0; i < 4; i++) // 枚举科目
{
passed = 0, failed = 0, total = 0, cnt = 0;
for (j = 0; j < n; j++)
{
if (!stu[j].del) // 枚举没被删除的同学
{
cnt++;
total += stu[j].score[i];
if (stu[j].score[i] >= 60) passed++;
else failed++;
}
}
cout << course[i] << endl << "Average Score: " << fixed << setprecision(2) << (cnt ? total * 1.0 / cnt + EPS : 0) << endl
<< "Number of passed students: " << passed << endl << "Number of failed students: " << failed << endl << endl;
}
for (int i = 0; i < n; i++) // 枚举没被删除的学生
{
if (!stu[i].del)
{
cnt1 = 0;
for (int j = 0; j < 4; j++) // 枚举他上的每门课程，计算多少门及格
{
if (stu[i].score[j] >= 60) cnt1++;
}
//更新统计通过i门课(i [0, 4]) 的学生数
if (!cnt1) p[0]++;
else
for (int k = 1; k <= cnt1; k++) p[k]++;
}
}
cout << "Overall:" << endl;
for (int i = 4; i >= 0; i--) cout << words[i] << p[i] << endl;
cout << endl;
}
else // 仅找班级号与cid相同的，且没被删除的学生
{
for (int i = 0; i < 4; i++)
{
passed = failed = total = cnt = 0;
for (int j = 0; j < n; j++)
{
if (!stu[j].del && stu[j].CID == cid)
{
cnt++;
total += stu[j].score[i];
if (stu[j].score[i] >= 60) passed++;
else failed++;
}
}
cout << course[i] << endl << "Average Score: " << fixed << setprecision(2) << (cnt ? total * 1.0 / cnt + EPS : 0) << endl
<< "Number of passed students: " << passed << endl << "Number of failed students: " << failed << endl << endl;
}
for (int i = 0; i < n; i++) // 枚举没被删除的，且在指定班级的所有学生
{
if (!stu[i].del && stu[i].CID == cid)
{
cnt1 = 0;
for (int j = 0; j < 4; j++) // 枚举他上的每门课程，计算多少门及格
{
if (stu[i].score[j] >= 60) cnt1++;
}
//更新统计通过i门课(i [0, 4]) 的学生数
if (!cnt1) p[0]++;
else
for (int k = 1; k <= cnt1; k++) p[k]++;
}
}
cout << "Overall:" << endl;
for (int i = 4; i >= 0; i--) cout << words[i] << p[i] << endl;
cout << endl;
}
}
int main()
{
cin.tie(0);
cin.sync_with_stdio(false);
#ifdef debug
freopen("E:\in.txt", "r", stdin);
freopen("E:\out.txt", "w", stdout);
#endif
// n = 0;
int choice;
bool flag = true;
while(flag)
{
Print_Menu();
cin >> choice;
switch(choice)
{
case 0: flag = false; break;
case 1: Add(); break;
case 2: Remove(); break;
case 3: Query(); break;
case 4: cout << "Showing the ranklist hurts students' self-esteem. Don't do that." << endl; break;
case 5: Statistics(); break;
}
}
#ifdef debug
fclose(stdin);
fclose(stdout);
#endif
return 0;
} /* 版本2 版本2与版本1的不同点是： 1. 合并了删除操作和查询操作的大部分代码。因为删除删除操作和查询的输入是一样的，并且，操作上也有大部分的重叠 2. 输出班级信息的部分，改为了两个函数，并且，将指定班级的输出和所有班级的输出合并了，因此只需要在特定的有选择语句的地方，除了判断输入数字是否与学生的班级号相等，再额外加上判断输入数字是否为0(因为为0时表示输出所有班级的信息，因而不再需要考虑学生的班级是否符合要求，直接全加上即可)...因而，合并了所有班级和指定班级的情况，大大精简了代码 又及，这个改进思路是从这个blog上看到的，然后我再以我最初敲好的代码，借鉴这个思路，作了一些简化和修改 http://blog.csdn.net/kun768/article/details/43816501 （据说还是汝佳老师的源代码），而且真是很简洁啊！一开始看到这道题的时候，我还以为不到将近200行一定搞不定，没想到...果然汝佳老师的思路就十分清晰，很清楚什么操作可以合并部分代码，什么情况可以合并大部分代码，因此代码也就简洁优美了很多 */
#include <iostream>
#include <iomanip>
#include <string>
#include <cstring>
#include <algorithm>
#include <cstdio>
//#define debug
using namespace std;
const int maxn = 1e5;
const double EPS = 1e-5;
int n = 0;
int CID, _score[4], sum;
string SID, name, s;
const string course[] = {"Chinese", "Mathematics", "English", "Programming"};
const string words[] = {"Number of students who failed all subjects: ", "Number of students who passed 1 or more subjects: ", "Number of students who passed 2 or more subjects: ", "Number of students who passed 3 or more subjects: ", "Number of students who passed all subjects: "};
struct student
{
int CID, score[5]; // Chinese, Math, English, Programming, total
bool del;
double average;
string name, SID;
}stu[maxn];
void Print_Menu()
{
cout << "Welcome to Student Performance Management System (SPMS)." << endl << endl << "1 - Add" << endl << "2 - Remove" << endl << "3 - Query" << endl << "4 - Show ranking" << endl << "5 - Show Statistics" << endl << "0 - Exit" << endl << endl;
}
int valid() // 检查是否合法，如果输入的SID已经输入过了，则该输入不合法，因而不处理该输入
{
for (int i = 0; i < n; i++)
{
if (!stu[i].del && stu[i].SID == s) return 0;
}
return 1;
}
int Rank (int k)
{
int cnt = 0;
for (int i = 0; i < n; i++)
{
if ( !stu[i].del && stu[i].score[4] > stu[k].score[4] ) cnt++;
}
return cnt + 1;
}
void Add()
{
while (1)
{
cout << "Please enter the SID, CID, name and four scores. Enter 0 to finish." << endl;
sum = 0;
student in;
cin >> s;
in.SID = s;
if (s == "0") break;
cin >> in.CID >> in.name;
for (int i = 0; i < 4; i++)
{
cin >> in.score[i];
sum += in.score[i];
}
if (!valid()) cout << "Duplicated SID." << endl;
else
{
in.score[4] = sum;
in.average = sum / 4.0 + EPS;
in.del = false;
stu[n++] = in;
}
}
}
void DQ(const int op) // op代表操作，如果为 0，表明输出的是要删除的，如果为 1，表明输入的只是需要查询
{
while (1)
{
cout << "Please enter SID or name. Enter 0 to finish." << endl;
cin >> s;
if (s == "0") break;
int cnt = 0;
for (int i = 0; i < n; i++)
{
if ( !stu[i].del && (stu[i].SID == s || stu[i].name == s) )
{
if (!op) //删除
{
stu[i].del = true;
++cnt;
}
else
{
char c = ' ';
cout << Rank(i) << c << stu[i].SID << c << stu[i].CID << c << stu[i].name << c;
for (int j = 0; j < 5; j++) cout << stu[i].score[j] << c;
cout << fixed << setprecision(2) << stu[i].average << endl;
}
}
}
if (!op) cout << cnt << " student(s) removed." << endl;
}
}
void output (const int no, const int type)
{
int sum = 0, cnt1 = 0, cnt2 = 0;
for (int i = 0; i < n; i++)
if ( !stu[i].del && (no == 0 || no == stu[i].CID) )
{
sum += stu[i].score[type];
if (stu[i].score[type] >= 60) cnt1++;
else cnt2++;
}
//#改到这里啦！
cout << "Average Score: " << fixed << setprecision(2) <<( (cnt1 + cnt2 != 0)?(sum * 1.0 / (cnt1 + cnt2) + EPS ): 0 )<< endl
<< "Number of passed students: " << cnt1 << endl << "Number of failed students: " << cnt2 << endl << endl;
}
void Print()
{
int p[5];
memset(p, 0, sizeof(p));
cout << "Please enter class ID, 0 for the whole statistics." << endl;
int num; cin >> num;
for (int i = 0; i < 4; i++)
{
cout << course[i] << endl;
output(num, i);
}
cout << "Overall:" << endl;
for (int i = 0; i < n; i++)
{
if ( !stu[i].del && ( num == 0 || stu[i].CID == num ) )
{
int tp = 0;
for (int j = 0; j < 4; j++)
if (stu[i].score[j] >= 60)
tp++;
if (!tp) p[0]++;
else
{
for (int k = 1; k <= tp; k++)
p[k]++;
}
}
}
for (int i = 4; i >= 0; i--)
cout << words[i] << p[i] << endl;
cout << endl;
}
int main()
{
cin.tie(0);
cin.sync_with_stdio(false);
#ifdef debug
freopen("E:\in.txt", "r", stdin);
freopen("E:\out.txt", "w", stdout);
#endif
int choice;
bool flag = true;
n = 0;
while(flag)
{
Print_Menu();
cin >> choice;
switch(choice)
{
case 0: flag = false; break;
case 1: Add(); break;
case 2: DQ(0); break;
case 3: DQ(1); break;
case 4: cout << "Showing the ranklist hurts students' self-esteem. Don't do that." << endl; break;
case 5: Print(); break;
}
}
#ifdef debug
fclose(stdin);
fclose(stdout);
#endif
return 0;
}