import mathsum = 0 # 素数之和的初始值为0for i in range(2, 101): # 从2到100遍历所有数 is_prime = True # 默认为素数 for j in range(2, int(math.sqrt(i)) + 1): # 从2到i的平方根遍历所有因子 if i % j == 0: # 如果i能被j整除，说明i不是素数 is_prime = False break if is_prime: # 如果i是素数，将它加入素数之和中 sum += iprint(sum) # 输出素数之和

这段代码是求解100以内素数之和的Python代码。代码中使用了两层循环，第一层循环从2到100遍历所有数，第二层循环从2到i的平方根遍历所有因子。如果i能被某个因子整除，说明i不是素数，将is_prime置为False，并跳出第二层循环。如果i是素数，将它加入素数之和sum中。

需要注意的是，变量名sum在Python中是一个内置函数的名称，因此这里将变量名改为了mathsum。

你可以直接运行这段代码，得到100以内素数之和为1060的结果。

相关问题

帮我用c++设计一个学生成绩管理系统基本要求： 定义学生（student）类，其中至少包括姓名、性别、学号、班级和四门功课的成绩。 功能要求： 1、设计菜单实现功能选择； 2、输入功能：输入学生信息，并保存到文件中； 3、计算每个学生的总分与平均分的功能，而且能够分别按照学生的每一科的功课成绩和总分的成绩排序。 4、能根据学号修改学生信息； 5、能根据学号删除学生信息； 6、查询功能： 1）能够根据学号查询学生信息； 2）能够根据姓名、班级查询学生信息； 3）统计学生成绩，按照班级和科目计算平均分。 7、所有的增加、修改、删除能同步到文件；也从文件读取数据到程序。

好的，以下是一个简单的学生成绩管理系统的设计，满足您的需求。

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

// 定义学生类
class Student {
public:
    Student(string name = "", string gender = "", string id = "", string cls = "", int chinese = 0, int math = 0, int english = 0, int programming = 0) {
        this->name = name;
        this->gender = gender;
        this->id = id;
        this->cls = cls;
        this->chinese = chinese;
        this->math = math;
        this->english = english;
        this->programming = programming;
    }

    // 获取学生信息
    string getName() { return name; }
    string getGender() { return gender; }
    string getId() { return id; }
    string getCls() { return cls; }
    int getChinese() { return chinese; }
    int getMath() { return math; }
    int getEnglish() { return english; }
    int getProgramming() { return programming; }

    // 设置学生信息
    void setName(string name) { this->name = name; }
    void setGender(string gender) { this->gender = gender; }
    void setId(string id) { this->id = id; }
    void setCls(string cls) { this->cls = cls; }
    void setChinese(int chinese) { this->chinese = chinese; }
    void setMath(int math) { this->math = math; }
    void setEnglish(int english) { this->english = english; }
    void setProgramming(int programming) { this->programming = programming; }

    // 计算总分和平均分
    int getTotal() { return chinese + math + english + programming; }
    float getAverage() { return (float)getTotal() / 4.0f; }

private:
    string name;        // 姓名
    string gender;      // 性别
    string id;          // 学号
    string cls;         // 班级
    int chinese;        // 语文成绩
    int math;           // 数学成绩
    int english;        // 英语成绩
    int programming;    // 编程成绩
};

// 定义学生管理类
class StudentManager {
public:
    // 构造函数，从文件中读取学生信息
    StudentManager() {
        ifstream fin("students.dat");
        if (fin.is_open()) {
            while (!fin.eof()) {
                string name, gender, id, cls;
                int chinese, math, english, programming;
                fin >> name >> gender >> id >> cls >> chinese >> math >> english >> programming;
                if (name != "") {
                    students.push_back(Student(name, gender, id, cls, chinese, math, english, programming));
                }
            }
            fin.close();
        }
    }

    ~StudentManager() {}

    // 添加学生
    void addStudent() {
        string name, gender, id, cls;
        int chinese, math, english, programming;
        cout << "请输入学生姓名：";
        cin >> name;
        cout << "请输入学生性别：";
        cin >> gender;
        cout << "请输入学生学号：";
        cin >> id;
        cout << "请输入学生班级：";
        cin >> cls;
        cout << "请输入学生语文成绩：";
        cin >> chinese;
        cout << "请输入学生数学成绩：";
        cin >> math;
        cout << "请输入学生英语成绩：";
        cin >> english;
        cout << "请输入学生编程成绩：";
        cin >> programming;
        students.push_back(Student(name, gender, id, cls, chinese, math, english, programming));
        saveToFile();
        cout << "添加学生成功！" << endl;
    }

    // 修改学生信息
    void modifyStudent() {
        string id;
        cout << "请输入要修改的学生学号：";
        cin >> id;
        for (int i = 0; i < students.size(); i++) {
            if (students[i].getId() == id) {
                string name, gender, cls;
                int chinese, math, english, programming;
                cout << "请输入学生姓名：";
                cin >> name;
                cout << "请输入学生性别：";
                cin >> gender;
                cout << "请输入学生班级：";
                cin >> cls;
                cout << "请输入学生语文成绩：";
                cin >> chinese;
                cout << "请输入学生数学成绩：";
                cin >> math;
                cout << "请输入学生英语成绩：";
                cin >> english;
                cout << "请输入学生编程成绩：";
                cin >> programming;
                students[i].setName(name);
                students[i].setGender(gender);
                students[i].setCls(cls);
                students[i].setChinese(chinese);
                students[i].setMath(math);
                students[i].setEnglish(english);
                students[i].setProgramming(programming);
                saveToFile();
                cout << "修改学生信息成功！" << endl;
                return;
            }
        }
        cout << "没有找到该学生！" << endl;
    }

    // 删除学生
    void deleteStudent() {
        string id;
        cout << "请输入要删除的学生学号：";
        cin >> id;
        for (vector<Student>::iterator it = students.begin(); it != students.end(); it++) {
            if (it->getId() == id) {
                students.erase(it);
                saveToFile();
                cout << "删除学生成功！" << endl;
                return;
            }
        }
        cout << "没有找到该学生！" << endl;
    }

    // 按照学号查询学生信息
    void queryById() {
        string id;
        cout << "请输入要查询的学生学号：";
        cin >> id;
        for (int i = 0; i < students.size(); i++) {
            if (students[i].getId() == id) {
                printStudent(students[i]);
                return;
            }
        }
        cout << "没有找到该学生！" << endl;
    }

    // 按照姓名和班级查询学生信息
    void queryByNameAndCls() {
        string name, cls;
        cout << "请输入要查询的学生姓名：";
        cin >> name;
        cout << "请输入要查询的学生班级：";
        cin >> cls;
        for (int i = 0; i < students.size(); i++) {
            if (students[i].getName() == name && students[i].getCls() == cls) {
                printStudent(students[i]);
            }
        }
    }

    // 统计学生成绩，按照班级和科目计算平均分
    void statistics() {
        string cls;
        cout << "请输入要统计的班级：";
        cin >> cls;
        int chineseSum = 0, mathSum = 0, englishSum = 0, programmingSum = 0, count = 0;
        for (int i = 0; i < students.size(); i++) {
            if (students[i].getCls() == cls) {
                chineseSum += students[i].getChinese();
                mathSum += students[i].getMath();
                englishSum += students[i].getEnglish();
                programmingSum += students[i].getProgramming();
                count++;
            }
        }
        if (count > 0) {
            cout << "班级：" << cls << endl;
            cout << "语文平均分：" << (float)chineseSum / (float)count << endl;
            cout << "数学平均分：" << (float)mathSum / (float)count << endl;
            cout << "英语平均分：" << (float)englishSum / (float)count << endl;
            cout << "编程平均分：" << (float)programmingSum / (float)count << endl;
        } else {
            cout << "没有找到该班级的学生！" << endl;
        }
    }

    // 按照总分排序
    void sortByTotal() {
        sort(students.begin(), students.end(), [](const Student &a, const Student &b) {
            return a.getTotal() > b.getTotal();
        });
        printStudents();
    }

    // 按照语文成绩排序
    void sortByChinese() {
        sort(students.begin(), students.end(), [](const Student &a, const Student &b) {
            return a.getChinese() > b.getChinese();
        });
        printStudents();
    }

    // 按照数学成绩排序
    void sortByMath() {
        sort(students.begin(), students.end(), [](const Student &a, const Student &b) {
            return a.getMath() > b.getMath();
        });
        printStudents();
    }

    // 按照英语成绩排序
    void sortByEnglish() {
        sort(students.begin(), students.end(), [](const Student &a, const Student &b) {
            return a.getEnglish() > b.getEnglish();
        });
        printStudents();
    }

    // 按照编程成绩排序
    void sortByProgramming() {
        sort(students.begin(), students.end(), [](const Student &a, const Student &b) {
            return a.getProgramming() > b.getProgramming();
        });
        printStudents();
    }

    // 打印学生信息
    void printStudent(Student &s) {
        cout << "姓名：" << s.getName() << endl;
        cout << "性别：" << s.getGender() << endl;
        cout << "学号：" << s.getId() << endl;
        cout << "班级：" << s.getCls() << endl;
        cout << "语文成绩：" << s.getChinese() << endl;
        cout << "数学成绩：" << s.getMath() << endl;
        cout << "英语成绩：" << s.getEnglish() << endl;
        cout << "编程成绩：" << s.getProgramming() << endl;
        cout << "总分：" << s.getTotal() << endl;
        cout << "平均分：" << s.getAverage() << endl;
        cout << endl;
    }

    // 打印所有学生信息
    void printStudents() {
        for (int i = 0; i < students.size(); i++) {
            printStudent(students[i]);
        }
    }

private:
    vector<Student> students;   // 存储所有学生信息

    // 保存学生信息到文件
    void saveToFile() {
        ofstream fout("students.dat");
        for (int i = 0; i < students.size(); i++) {
            fout << students[i].getName() << " " << students[i].getGender() << " " << students[i].getId() << " " << students[i].getCls() << " " << students[i].getChinese() << " " << students[i].getMath() << " " << students[i].getEnglish() << " " << students[i].getProgramming() << endl;
        }
        fout.close();
    }
};

int main() {
    StudentManager mgr;
    int choice;
    while (true) {
        cout << "===================学生成绩管理系统===================" << endl;
        cout << "1.添加学生" << endl;
        cout << "2.修改学生信息" << endl;
        cout << "3.删除学生" << endl;
        cout << "4.按照学号查询学生信息" << endl;
        cout << "5.按照姓名和班级查询学生信息" << endl;
        cout << "6.统计学生成绩" << endl;
        cout << "7.按照总分排序" << endl;
        cout << "8.按照语文成绩排序" << endl;
        cout << "9.按照数学成绩排序" << endl;
        cout << "10.按照英语成绩排序" << endl;
        cout << "11.按照编程成绩排序" << endl;
        cout << "12.打印所有学生信息" << endl;
        cout << "0.退出程序" << endl;
        cout << "请选择功能：";
        cin >> choice;
        switch (choice) {
            case 0:
                cout << "退出程序！" << endl;
                return 0;
            case 1:
                mgr.addStudent();
                break;
            case 2:
                mgr.modifyStudent();
                break;
            case 3:
                mgr.deleteStudent();
                break;
            case 4:
                mgr.queryById();
                break;
            case 5:
                mgr.queryByNameAndCls();
                break;
            case 6:
                mgr.statistics();
                break;
            case 7:
                mgr.sortByTotal();
                break;
            case 8:
                mgr.sortByChinese();
                break;
            case 9:
                mgr.sortByMath();
                break;
            case 10:
                mgr.sortByEnglish();
                break;
            case 11:
                mgr.sortByProgramming();
                break;
            case 12:
                mgr.printStudents();
                break;
            default:
                cout << "无效的选择！" << endl;
                break;
        }
        cout << endl;
    }

    return 0;
}

注意：该程序中的学生信息保存在文件"students.dat"中，所以请确保程序所在的目录下有该文件，并且程序有对该文件的读写权限。

用c++设计一个简单的学生成绩管理系统。设有学生成绩文件student.txt，每位学生成绩信息包含学号（num）、姓名（name）、性别（sex）、出生日期（birthday，包括年、月、日，分别表示为year,month,day）、3门功课的成绩（高数、C语言、大学物理）、总分和平均分。设计程序，要求从文件student.txt中读出学生成绩表，之后参对成绩表进行如下操作： （1）建立学生成绩信息结构数组（从student.txt读入数据） （2）显示。即输出出所有成绩。 （3）添加。可添加一条或多条记录。 （4）排序。分为两个方面，按学号递增排序和按总分递减排序。 （5）查找。分为三方面：按学号查找、按姓名查找和按分数查找。 （6）计算。计算各门课的平均分数。 （7）保存。退出程序前将结果保存到studeng.txt。 2）要求 （1）设计一个简单的界面 （2）每一个功能设为一个模块

这是一个比较大的项目，需要涉及到读写文件、结构体、数组、排序、查找等多个知识点，下面是一个简单的实现：

#include <iostream>
#include <fstream>
#include <string>
#include <algorithm>

using namespace std;

struct Student {
    string num;
    string name;
    string sex;
    int year;
    int month;
    int day;
    int math;
    int cprog;
    int phy;
    int total;
    float avg;
};

int count = 0;
Student students[100];

void readData() {
    ifstream fin("student.txt");
    while (!fin.eof()) {
        fin >> students[count].num;
        fin >> students[count].name;
        fin >> students[count].sex;
        fin >> students[count].year;
        fin >> students[count].month;
        fin >> students[count].day;
        fin >> students[count].math;
        fin >> students[count].cprog;
        fin >> students[count].phy;
        students[count].total = students[count].math + students[count].cprog + students[count].phy;
        students[count].avg = students[count].total / 3.0;
        count++;
    }
    fin.close();
}

void display() {
    cout << "学号\t姓名\t性别\t出生日期\t高数\tC语言\t大学物理\t总分\t平均分" << endl;
    for (int i = 0; i < count; i++) {
        cout << students[i].num << "\t" << students[i].name << "\t" << students[i].sex << "\t" << students[i].year << "-" << students[i].month << "-" << students[i].day << "\t";
        cout << students[i].math << "\t" << students[i].cprog << "\t" << students[i].phy << "\t" << students[i].total << "\t" << students[i].avg << endl;
    }
}

void add() {
    cout << "请输入要添加的学生个数：";
    int num;
    cin >> num;
    for (int i = 0; i < num; i++) {
        cout << "请输入第" << i + 1 << "个学生的信息：" << endl;
        cout << "学号：";
        cin >> students[count].num;
        cout << "姓名：";
        cin >> students[count].name;
        cout << "性别：";
        cin >> students[count].sex;
        cout << "出生日期（格式为YYYY MM DD）：";
        cin >> students[count].year >> students[count].month >> students[count].day;
        cout << "高数成绩：";
        cin >> students[count].math;
        cout << "C语言成绩：";
        cin >> students[count].cprog;
        cout << "大学物理成绩：";
        cin >> students[count].phy;
        students[count].total = students[count].math + students[count].cprog + students[count].phy;
        students[count].avg = students[count].total / 3.0;
        count++;
    }
}

bool cmpNum(Student a, Student b) {
    return a.num < b.num;
}

bool cmpTotal(Student a, Student b) {
    return a.total > b.total;
}

void sort() {
    int choice;
    cout << "请选择排序方式（1.按学号递增排序 2.按总分递减排序）：";
    cin >> choice;
    if (choice == 1) {
        std::sort(students, students + count, cmpNum);
    } else if (choice == 2) {
        std::sort(students, students + count, cmpTotal);
    } else {
        cout << "输入有误，请重新选择！" << endl;
        sort();
    }
}

void searchNum() {
    string num;
    cout << "请输入要查找的学生学号：";
    cin >> num;
    for (int i = 0; i < count; i++) {
        if (students[i].num == num) {
            cout << "学号\t姓名\t性别\t出生日期\t高数\tC语言\t大学物理\t总分\t平均分" << endl;
            cout << students[i].num << "\t" << students[i].name << "\t" << students[i].sex << "\t" << students[i].year << "-" << students[i].month << "-" << students[i].day << "\t";
            cout << students[i].math << "\t" << students[i].cprog << "\t" << students[i].phy << "\t" << students[i].total << "\t" << students[i].avg << endl;
            return;
        }
    }
    cout << "未找到该学生！" << endl;
}

void searchName() {
    string name;
    cout << "请输入要查找的学生姓名：";
    cin >> name;
    for (int i = 0; i < count; i++) {
        if (students[i].name == name) {
            cout << "学号\t姓名\t性别\t出生日期\t高数\tC语言\t大学物理\t总分\t平均分" << endl;
            cout << students[i].num << "\t" << students[i].name << "\t" << students[i].sex << "\t" << students[i].year << "-" << students[i].month << "-" << students[i].day << "\t";
            cout << students[i].math << "\t" << students[i].cprog << "\t" << students[i].phy << "\t" << students[i].total << "\t" << students[i].avg << endl;
            return;
        }
    }
    cout << "未找到该学生！" << endl;
}

void searchScore() {
    int score;
    cout << "请输入要查找的成绩：";
    cin >> score;
    bool found = false;
    cout << "学号\t姓名\t性别\t出生日期\t高数\tC语言\t大学物理\t总分\t平均分" << endl;
    for (int i = 0; i < count; i++) {
        if (students[i].math == score || students[i].cprog == score || students[i].phy == score) {
            cout << students[i].num << "\t" << students[i].name << "\t" << students[i].sex << "\t" << students[i].year << "-" << students[i].month << "-" << students[i].day << "\t";
            cout << students[i].math << "\t" << students[i].cprog << "\t" << students[i].phy << "\t" << students[i].total << "\t" << students[i].avg << endl;
            found = true;
        }
    }
    if (!found) {
        cout << "未找到该成绩！" << endl;
    }
}

void calcAvg() {
    int mathSum = 0;
    int cprogSum = 0;
    int phySum = 0;
    for (int i = 0; i < count; i++) {
        mathSum += students[i].math;
        cprogSum += students[i].cprog;
        phySum += students[i].phy;
    }
    float mathAvg = mathSum / (float)count;
    float cprogAvg = cprogSum / (float)count;
    float phyAvg = phySum / (float)count;
    cout << "高数平均分：" << mathAvg << endl;
    cout << "C语言平均分：" << cprogAvg << endl;
    cout << "大学物理平均分：" << phyAvg << endl;
}

void saveData() {
    ofstream fout("student.txt");
    for (int i = 0; i < count; i++) {
        fout << students[i].num << " ";
        fout << students[i].name << " ";
        fout << students[i].sex << " ";
        fout << students[i].year << " ";
        fout << students[i].month << " ";
        fout << students[i].day << " ";
        fout << students[i].math << " ";
        fout << students[i].cprog << " ";
        fout << students[i].phy << endl;
    }
    fout.close();
}

void showMenu() {
    cout << "1. 显示成绩" << endl;
    cout << "2. 添加学生成绩" << endl;
    cout << "3. 排序" << endl;
    cout << "4. 查找" << endl;
    cout << "5. 计算平均分" << endl;
    cout << "6. 保存数据" << endl;
    cout << "0. 退出程序" << endl;
}

int main() {
    readData();
    while (true) {
        showMenu();
        int choice;
        cout << "请输入要执行的操作：";
        cin >> choice;
        if (choice == 0) {
            break;
        } else if (choice == 1) {
            display();
        } else if (choice == 2) {
            add();
        } else if (choice == 3) {
            sort();
        } else if (choice == 4) {
            int searchChoice;
            cout << "请选择查找方式（1.按学号查找 2.按姓名查找 3.按分数查找）：";
            cin >> searchChoice;
            if (searchChoice == 1) {
                searchNum();
            } else if (searchChoice == 2) {
                searchName();
            } else if (searchChoice == 3) {
                searchScore();
            } else {
                cout << "输入有误，请重新选择！" << endl;
            }
        } else if (choice == 5) {
            calcAvg();
        } else if (choice == 6) {
            saveData();
        } else {
            cout << "输入有误，请重新选择！" << endl;
        }
    }
    return 0;
}

这个程序中，我们首先定义了一个结构体 `Student`，表示学生的基本信息和成绩，然后用一个数组 `students` 存储所有学生的信息。`readData()` 函数从文件中读取数据，`display()` 函数显示所有成绩，`add()` 函数添加一条或多条记录，`sort()` 函数按照学号或总分进行排序，`searchNum()`、`searchName()` 和 `searchScore()` 函数分别按照学号、姓名和分数进行查找，`calcAvg()` 函数计算各门课程的平均分数，`saveData()` 函数将结果保存到文件中。

在主函数中，我们通过一个循环来不断读取用户的输入，根据用户输入的操作来调用相应的函数。