GPA_calculator.txt

#include <iostream>
#include <string>
#include <math.h>
#include <iomanip>
#include <sstream>
using namespace std;
int Search[41];

class Student{
public:
    int SumGrade;
    int Credits;
    int Grade;
    bool IsNew;
public:
    Student();
    double getGrade();
    void RefreshData(int Credit,int GP);
};
Student::Student(){
    SumGrade = 0;
    Credits = 0;
    Grade = 0;
    IsNew = true;
}
double Student::getGrade(){
    return double(Grade)/10;
}
void Student::RefreshData(int Credit,int GP){
    if(IsNew) {
        IsNew = false;
    }
    else{
        Search[Grade] -= 1;
    }
    SumGrade += (Credit*GP);
    Credits += Credit;
    Grade = (SumGrade+Credits-1)/Credits;
    Search[Grade] += 1;
}

int Grade2GP(string &s){
    if(s=="A+") return 40;
    if(s=="A=") return 40;
    if(s=="A-") return 37;
    if(s=="B+") return 33;
    if(s=="B=") return 30;
    if(s=="B-") return 27;
    if(s=="C+") return 23;
    if(s=="C=") return 20;
    if(s=="C-") return 17;
    if(s=="D+") return 13;
    if(s=="D=") return 10;
    if(s=="F=") return 0;
    return 0;
};

int main() {
    int NumOfStu, NumOfEve;
    cin>>NumOfStu>>NumOfEve;
    cin.ignore();
    Student *StuList = new Student[NumOfStu];
    string order;
    int ID;             //student number
    int Credit;         //Credit of each class
    string level;       //level eg:A+
    while(NumOfEve){
        getline(cin,order);
        istringstream istr(order);
        int type;           //order type
        istr>>type;
        switch (type) {
            case 1:
            {
                istr>>ID;
                istr>>Credit;
                istr>>level;
                StuList[ID-1].RefreshData(Credit,Grade2GP(level));
                break;
            }
            case 2:
                istr>>ID;
                cout<<setiosflags(ios::fixed)<<setprecision(1)<<StuList[ID-1].getGrade()<<endl;
                break;
            case 3:
                double input;
                istr>>input;
                int number = input*10;
                cout<<Search[number]<<endl;
                break;
            defult:
                break;
        }
        NumOfEve--;
    }
}