Student Management System (document version)

import time
import them

# Set a list to store all student information (each student is a dictionary)
info_list = []


def print_menu():
    print("---------------------------")
    print("Student Management System V1.0")
    print("1: add student")
    print("2: delete student")
    print("3: Modify students")
    print("4: query students")
    print("5: show all students")
    print("6: save data")
    print("7: Exit the system")
    print("---------------------------")


def add_new_info():
    """Add student information"""
    global info_list

    new_name = input("Please enter your name:")
    new_tel = input("Please enter your phone number:")
    new_qq = input("Please enter QQ:")

    for temp_info in info_list:
        if temp_info['name'] == new_name:
            print("This username is already occupied, please re-enter")
            return # If a function only has a return, it is equivalent to letting the function end without a return value

    # Define a dictionary to store the user's student information (this is a dictionary)
    info = {}

    # add data to dictionary
    info["name"] = new_name
    info["tel"] = new_tel
    info["qq"] = new_qq

    # add this dictionary to the list
    info_list.append(info)


def del_info():
    """Delete student information"""
    global info_list

    del_num = int(input("Please enter the serial number to delete:"))
    if 0 <= del_num < len(info_list):
        del_flag = input("Are you sure you want to delete? yes or no")
        if del_flag == "yes":
            from info_list [from_num]
    else:
        print("The input serial number is wrong, please re-enter")


def modify_info():
    """Modify student information"""
    global info_list

    modify_num = int(input("Please enter the serial number to be modified:"))
    if 0 <= modify_num < len(info_list):
        print("The information you want to modify is: ")
        print("name:%s, tel:%s, QQ:%s" % (info_list[modify_num]['name'],
            info_list[modify_num]['tel'],info_list[modify_num]['qq']))
        info_list[modify_num]['name'] = input("Please enter a new name:")
        info_list[modify_num]['tel'] = input("Please enter a new phone number:")
        info_list[modify_num]['qq'] = input("Please enter a new QQ:")
    else:
        print("The input serial number is wrong, please re-enter")


def search_info():
    """Query student information"""
    search_name = input("Please enter the name of the student you want to query:")
    for temp_info in info_list:
        if temp_info['name'] == search_name:
            print("The query information is as follows:")
            print("name:%s, tel:%s, QQ:%s" % (temp_info['name'],
                temp_info['tel'], temp_info['qq']))
            break
    else:
        print("There is no information you are looking for....")


def print_all_info():
    """Traverse student information"""
    print("Serial number\tName\t\tMobile number\t\tQQ")
    i = 0
    for temp in info_list:
        # temp is a dictionary
        print("%d\t%s\t\t%s\t\t%s" % (i, temp['name'], temp['tel'], temp['qq']))
        i += 1


def save_data():
    """Load previously stored data"""
    f = open("info_data.data", "w")
    f.write(str(info_list))
    f.close()


def load_data():
    """Load previously stored data"""
    global info_list
    f = open("info_data.data")
    content = f.read()
    info_list = eval(content)
    f.close()

def main():
    """Used to control the entire process"""

    # Load data (only once)
    load_data()

    while True:
        # 1. Print function
        print_menu()

        # 2. Get the user's choice
        num = input("Please enter the operation to be performed (number):")

        # 3. According to the user's choice, do the corresponding things
        if num == "1":
            # add students
            add_new_info()
        elif num == "2":
            # delete student
            del_info ()
        elif num == "3":
            # modify students
            modify_info()
        elif num == "4":
            # query students
            search_info()
        elif num == "5":
            # loop through all the information
            print_all_info()
        elif num == "6":
            # save data to file
            save_data()
        elif num == "7":
            # Exit system
            exit_flag = input("Dear, are you sure you want to exit?~~~~(>_<)~~~~(yes or no) ")
            if exit_flag == "yes":
                break
        else:
            print("Incorrect input, please re-enter...")

            os.system('cls')
# start of program
main()