DANH SACH SINH VIEN - 3

#include<iostream>
#include<cmath>
#include<iomanip>
#include<string>
#include<stdio.h>
#include<vector>
#include<sstream>
using namespace std;
struct SinhVien{
    string MaSinhVien;
    string TenSinhVien;
    string Lop;
    string NgaySinh;
    float GPA;
};
string ChuanHoaNgaySinh(string s){
    for(int j = 0 ; j < s.length();j++)
     {
         if(s[2] != '/')
         {
             s.insert(0,"0");
         }
         else if(s[5] !='/')
         {
             s.insert(3,"0");
         }
     }
    return s;
}
void ChuanHoa(string &s){
    s[0] = toupper(s[0]);
    for(int i = 1; i < s.length(); i++){
        s[i] = tolower(s[i]);
    }

}
string ChuanHoaHoTen(string &s){
    vector<string> v;
    stringstream ss(s);
    string tmp;
    string res="";
    while(ss>>tmp) v.push_back(tmp);
    for(int i = 0; i<v.size(); i++){
        ChuanHoa(v[i]);
    }
    for(int i = 0; i<v.size(); i++){
        res+=v[i];
        if(i!=v.size()-1){
            res+=' ';
        }
    }
    return res;
}
string MaSinhVien(int i){
    stringstream ss;
    string s;
    ss << "B20DCCN"<< setfill('0') << setw(3) <<i+1;
    ss >> s;
    return s;
}
void nhap(struct SinhVien sv[],int N){
    for(int i = 0; i<N; i++){
        scanf("\n");
        fflush(stdin);
        sv[i].MaSinhVien = MaSinhVien(i);
        fflush(stdin);
        getline(cin, sv[i].TenSinhVien);
        sv[i].TenSinhVien = ChuanHoaHoTen(sv[i].TenSinhVien);
        fflush(stdin);
        getline(cin, sv[i].Lop);
        fflush(stdin);
        getline(cin, sv[i].NgaySinh);
        sv[i].NgaySinh = ChuanHoaNgaySinh(sv[i].NgaySinh);
        fflush(stdin);
        cin >> sv[i].GPA;
        scanf("\n");
    }
}
void sapxep(struct SinhVien sv[], int N){
    for(int i = 0; i<N-1; i++){
        for(int j = i+1; j<N; j++){
            if(sv[i].GPA<sv[j].GPA){
                struct SinhVien temp = sv[i];
                sv[i] = sv[j];
                sv[j] = temp;
            }
        }
    }
}
void in(struct SinhVien sv[], int N){
    for(int i = 0; i<N; i++){
        cout << sv[i].MaSinhVien << " " << sv[i].TenSinhVien << " " << sv[i].Lop << " " << sv[i].NgaySinh << " " << fixed << setprecision(2) << sv[i].GPA << endl;
    }
}

int main(){
    struct SinhVien ds[50];
    int N;
    cin >> N;
    nhap(ds, N);
    sapxep(ds,N);
    in(ds, N);
    return 0;
}