UVa 12412 – A Typical Homework

```#include <bits/stdc++.h>
using namespace std;

const double EPS = 1e-5;
const int maxn = 1024;
int cnt = 0;

struct stu{
string SID, name;
int CID;
int score[5];
bool removed;
}all[maxn];

{
cout << "Welcome to Student Performance Management System (SPMS)." << endl << endl;
cout << "1 - Add" << endl;
cout << "2 - Remove" << endl;
cout << "3 - Query" << endl;
cout << "4 - Show ranking" << endl;
cout << "5 - Show Statistics" << endl;
cout << "0 - Exit" << endl;
cout << endl;
}

int Rank(const int x)
{
int t = all[x].score[0];
int high = 0;
for(int i = 0; i < cnt; i++)
if(!all[i].removed && all[i].score[0] > t)
high++;
return high + 1;
}

{
while(true){
loop:
cout << "Please enter the SID, CID, name and four scores. Enter 0 to finish." << endl;
stu in; cin >> in.SID;
if(in.SID == "0") break;
cin >> in.CID >> in.name >> in.score[1] >> in.score[2] >> in.score[3] >> in.score[4];
for(int i = 0; i < cnt; i++)
if(!all[i].removed && in.SID == all[i].SID){
cout << "Duplicated SID." << endl;
goto loop;
}
in.score[0] = in.score[1] + in.score[2] + in.score[3] + in.score[4];
in.removed = false;
all[cnt++] = in;
}
}

void DQ(const int isq)
{
while(true){
cout << "Please enter SID or name. Enter 0 to finish." << endl;
string str; cin >> str;
if(str == "0") break;
int rem_cnt = 0;
for(int i = 0; i < cnt; i++){
if(!all[i].removed && (str == all[i].SID || str == all[i].name)) {
if(isq){
printf("%d %s %d %s %d %d %d %d %d %.2f\n", Rank(i), all[i].SID.c_str(), all[i].CID, all[i].name.c_str(),
all[i].score[1], all[i].score[2], all[i].score[3], all[i].score[4], all[i].score[0], all[i].score[0]/4.0+EPS);
}
else{
all[i].removed = true;
rem_cnt++;
}
}
}
if(!isq) printf("%d student(s) removed.\n", rem_cnt);
}
}

void output(const int ID, const int type)
{
int sum = 0, cnt1 = 0, cnt2 = 0;
for(int i = 0; i < cnt; i++){
if(!all[i].removed && (ID==0 || all[i].CID==ID)){
sum += all[i].score[type];
if(all[i].score[type] >= 60) cnt1++;
else cnt2++;
}
}
printf("Average Score: %.2f\n", cnt1+cnt2 == 0 ? 0 : sum*1.0/(cnt1+cnt2)+EPS);
printf("Number of passed students: %d\n", cnt1);
printf("Number of failed students: %d\n", cnt2);
printf("\n");
}

void stat()
{
puts("Please enter class ID, 0 for the whole statistics.");
int ID; cin >> ID;
cout << "Chinese" << endl; output(ID, 1);
cout << "Mathematics" << endl; output(ID, 2);
cout << "English" << endl; output(ID, 3);
cout << "Programming" << endl; output(ID, 4);
cout << "Overall:" << endl;
int okcnt[5]; memset(okcnt, 0, sizeof(okcnt));
for(int i = 0; i < cnt; i++){
if(!all[i].removed && (ID==0 || all[i].CID==ID)){
int ok = 0;
for(int j = 1; j <= 4; j++)
if(all[i].score[j] >= 60)
ok++;
okcnt[ok]++;
}
}
printf("Number of students who passed all subjects: %d\n", okcnt[4]);
printf("Number of students who passed 3 or more subjects: %d\n", okcnt[3]+okcnt[4]);
printf("Number of students who passed 2 or more subjects: %d\n", okcnt[2]+okcnt[3]+okcnt[4]);
printf("Number of students who passed 1 or more subjects: %d\n", okcnt[1]+okcnt[2]+okcnt[3]+okcnt[4]);
printf("Number of students who failed all subjects: %d\n", okcnt[0]);
printf("\n");
}

int main()
{
//freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);

while(true){