Student Management

class StudentManager:
    def __init__(self):
        self.students = []
        self.next_id  = 1

    def calc_grade(self, marks):
        if marks >= 90: return "A+"
        if marks >= 80: return "A"
        if marks >= 70: return "B"
        if marks >= 60: return "C"
        if marks >= 33: return "D"
        return "F"

    def add(self, name, marks):
        grade = self.calc_grade(marks)
        self.students.append({
            "id":    self.next_id,
            "name":  name,
            "marks": marks,
            "grade": grade
        })
        print(f"Student add hua - ID:{self.next_id} {name} ({grade})")
        self.next_id += 1

    def show_all(self):
        if not self.students:
            print("Koi student nahi hai!")
            return
        sorted_s = sorted(self.students, key=lambda x: x["marks"], reverse=True)
        print(f"\n{'ID':4} {'Naam':15} {'Marks':8} {'Grade'}")
        print("-" * 35)
        for s in sorted_s:
            print(f"  {s['id']:2}   {s['name']:13}  {s['marks']:6}   {s['grade']}")

    def topper(self):
        if self.students:
            t = max(self.students, key=lambda x: x["marks"])
            print(f"Topper: {t['name']} - {t['marks']} marks ({t['grade']})")

    def search(self, name):
        found = [s for s in self.students if name.lower() in s["name"].lower()]
        if found:
            for s in found:
                print(f"  Mila: {s['name']} - {s['marks']} ({s['grade']})")
        else:
            print("Student nahi mila!")

sm = StudentManager()
while True:
    print("\n1. Student add karo")
    print("2. Sab dikhaao")
    print("3. Topper dekho")
    print("4. Search karo")
    print("5. Baahar jao")
    ch = input("Choice: ")
    if ch == "1":
        sm.add(input("Naam: "), int(input("Marks (out of 100): ")))
    elif ch == "2": sm.show_all()
    elif ch == "3": sm.topper()
    elif ch == "4": sm.search(input("Naam search karo: "))
    elif ch == "5": break