task 2,3,4 (oop lab 4) 3rd sem

#include<bits/stdc++.h>
#include<ctime>
using namespace std;
class student
{
private:
    string name;
    int day,month,year,id;
    float cgpa;
public:
    void setname(string NAME)
    {
        name=NAME;
    }
    void setdob(int DAY,int MONTH,int YEAR)
    {
        if(DAY<=31&&MONTH<=12)
        {
            day=DAY;
            month=MONTH;
            year=YEAR;
        }
        else
            cout<<"Invalid input"<<endl;
    }
    void setid(int ID)
    {
        id=ID;
    }
    void setcgpa(float CGPA)
    {
        cgpa=CGPA;
    }
    void setinfo(string name1,int day1,int month1,int year1,int id1,float cgpa1)
    {
        setname(name1);
        setdob(day1,month1,year1);
        setid(id1);
        setcgpa(cgpa1);
    }
    string getname() const
    {
        return name;
    }
    int getday() const
    {
        return day;
    }
    int getmonth() const
    {
        return month;
    }
    int getyear() const
    {
        return year;
    }
    int getid() const
    {
        return id;
    }
    float getcgpa() const
    {
        return cgpa;
    }
    int getage(int day2,int month2,int year2) const
    {
        if(day2<=31&&month2<=12&&year2>year)
        {
            int age;
            age=year2-year;
            if(month2<month)
                age--;
            else if(month2==month)
            {
                if(day2<day)
                    age--;
            }
            cout<<"Age is "<<age<<endl;
        }
        else
            cout<<"Invalid input"<<endl;
    }
    int getage() const
    {
        time_t now = time(0);
        tm *ltm = localtime(&now);
        int year2=1900 + ltm->tm_year;
        int month2= 1 + ltm->tm_mon;
        int day2=ltm->tm_mday ;
        if(day2<=31&&month2<=12&&year2>year)
        {
            int age;
            age=year2-year;
            if(month2<month)
                age--;
            else if(month2==month)
            {
                if(day2<day)
                    age--;
            }
            cout<<"Age is (using system) "<<age<<endl;
        }
        else
            cout<<"Invalid input"<<endl;
    }
    void getinfo()
    {
        cout<<"Name is "<<getname()<<endl;
        cout<<"Date of birth is "<<getday()<<"/"<<getmonth()<<"/"<<getyear()<<endl;
        cout<<"ID is "<<getid()<<endl;
        cout<<"CGPA is "<<getcgpa()<<endl;
    }
    student()
    {
        name="";
        day=0;
        month=0;
        year=0;
        id=0;
        cgpa=0;
    }
};
int main()
{
    student s1;
    s1.setinfo("Yushua",6,5,2011,18,3.9);
    s1.getinfo();
    s1.getage(27,1,2020);
    s1.getage();
}