Một ví dụ về sử dụng template

#include <iostream.h>
#include <stdlib.h>
#include <conio.h>
class sv
{
    private :
       char ten[100];
      float Diem;
   public:
       sv()
      {
          Diem=0;
      }
      sv(char a[],float D)
      {
            strcpy(ten,a);
         Diem=D;
      }
      sv(sv&a)
      {
          Diem = a.Diem;
              strcpy(ten,a.ten);
      }
      void set_sv(char a[],float D)
      {
            strcpy(ten,a);
         Diem=D;
      }
      float get_diem()const
      {
          return Diem;
      }
      char* get_ten()
      {
          return ten;
      }
      friend ostream&operator <<(ostream&out,sv&);
      friend istream&operator>>(istream&in,sv&);
      operator float()
      {
          return float(Diem);
      }


};
ostream&operator <<(ostream&out,sv&a)
{
     cout<<"\n\n\t\t\tTen "<<a.ten<<endl;
   cout<<"\t\t\tDiem "<<a.Diem<<endl;
}
istream&operator>>(istream&in,sv&a)
{
    cout<<"\t\t\tNhap ten ";
   cin.ignore();
   cin.getline(a.ten,50);
   cout<<"\t\t\tNhap diem ";
   cin>>a.Diem;

}
int ucln(int a,int b)
{
    int r;
   while(b)
   {
       r = a%b;
      a = b;
      b=r;
   }
   return a;
}

class phanso
{
    private:
       float tu,mau;
   public:
       phanso(float a=1,float b=1)
      {
          if(b)
         {
             tu = a;
            mau = b;
         }
         else
         {
             tu =1;
            mau=1;
         }
      }
      void set_phanso(float a,float b)
      {
          tu =a;
         mau = b;
      }
      void nhap()
      {
          cout<<"\t\t\tNhap du lieu cho phan so "<<endl;
         cout<<"\t\t\tTu ";
         cin>>tu;
         cout<<"\t\t\tMau ";
         cin>>mau;
         toigian();
      }
      void toigian()
      {
          int t=ucln(tu,mau);
         tu = tu/t;
         mau = mau/t;
      }
      operator float()
      {
          return float(tu/mau);
      }
        friend ostream&operator <<(ostream&out,phanso&a);
      friend istream&operator >>(istream&in,phanso&a);

};
ostream&operator<<(ostream&out,phanso&a)
{
    out<<a.tu<<"/"<<a.mau<<"->";
}
istream&operator >>(istream&in,phanso&a)
{
    cout<<"\t\tTu ";
   cin>>a.tu;
   cout<<"\t\tMau ";
   cin>>a.mau;
}
template <class T,int n>
class set
{
    private:
       T data[n];
      int spt;
   public:
       set()
      {
          spt=0;
      }
        set(const set&a)
      {
          for(int i=0;i<a.spt;i++)
             data[i]=a.data[i];
            spt = a.spt;
      }
      void them(T&a);
      bool search(T&a);
      friend ostream& operator<<(ostream&out,set<T,n>&a);
      friend set operator +(set&a,set&b);
      friend set operator *(set&a,set&b);
      friend set operator -(set&a,set&b);
      set operator =(const set&b)
      {
              for(int i=0;i<b.spt;i++)
                   data[i]=b.data[i];
              spt=b.spt;
            return (*this);
      }

};
template <class T,int n>
void set<T,n>::them(T&a)
{
    if(spt<n)
       data[spt++]=a;
   else
       cout<<"\t\tMang da day rui khong them duoc nua dau "<<endl;
}
template <class T,int n>
bool set<T,n>::search(T&a)
{
    for(int i=0;i<spt;i++)
       if(data[i]==a)
          return true;
        return false;
}
template <class T,int n>
ostream&operator<<(ostream&out,set<T,n>&a)
{
   if(a.spt==0)
       out<<" rong "<<endl;
    for(int i=0;i<a.spt;i++)
   {
       out<<a.data[i];
          if(i<a.spt-1)
          cout<<"->";
   }
}
template <class T,int n>
set<T,n> operator +(set<T,n>&a,set<T,n>&b)
{
    set<T,n> r(a);

     for(int i=0;i<b.spt;i++)
          if(!a.search(b.data[i]))
                r.them(b.data[i]);



   return r;
}
template <class T,int n>
set<T,n> operator -(set<T,n>&a,set<T,n>&b)
{
    set<T,n> r;
    for(int i=0;i<a.spt;i++)
       if(!b.search(a.data[i]))
          r.them(a.data[i]);
    return r;
}
template <class T,int n>
set<T,n> operator *(set<T,n>&a,set<T,n>&b)
{
    set<T,n> r;

    for(int i=0;i<a.spt;i++)
       if(b.search(a.data[i]))

          r.them(a.data[i]);

         return r;
}
void main()
{
      set<float,100> a;
   set<float,100> c;
   set<float,100> d;
   set<float,100> e;
   set<float,100> f;
   set<sv,100> g;
   set<phanso,100> b;
   int n,m,l;
   float r;
   sv A;
   phanso s;
   cout<<"\t\t\tNhap so luong cac so thu ";
   cin>>n;
   for(int i=0;i<n;i++)
   {
       cout<<" nhap so thu "<<(i+1)<<":";
      cin>>r;
      a.them(r);
   }clrscr();
   cout<<"\t\t\tNhap so luong phan so ";
   cin>>m;
   for(int i=0;i<m;i++)
   {
       cout<<"\t\t\tNhap phan so thu "<<(i+1)<<endl;
      cin>>s;
      b.them(s);
      c.them(s);clrscr();
   }

   clrscr();
   cout<<"\t\t\tNhap so luong cac sinh vien ";
   cin>>l;
   for(int i=0;i<l;i++)
    {
       cout<<"\t\t\tNhap du lieu cho sinh vien thu "<<(i+1)<<endl;
      cin>>A;
      g.them(A);
      clrscr();
   }
   clrscr();
   textcolor(YELLOW+RED);
   cprintf("%s","\t\t\tchuong trinh da gan cac so 1 cach tu dong ta duoc ");
   cout<<"\n\nday so thuc vua nhap  "<<endl;
   cout<<a;
   cout<<"\n\nday phan so vua nhap  "<<endl;
      cout<<b;
   cout<<"\n\tDay sinh vien vua nhap "<<endl;
   cout<<g;
   getch();clrscr();
   d = a+c;
   cout<<"\n\n hop cua hai tap hop phan so va so thuc  la "<<endl;;
   cout<<d;
   e=a*c;
   cout<<"\n\n giao cua hai tap so thuc va phan so  la "<<endl;
   cout<<e;
   cout<<"\n\nhieu cua hai tap so thuc va phan so la "<<endl;
   f=a-c;
   cout<<f;

    getch();
}

Ví dụ về quá tải toán tử

#include <iostream.h>
#include <conio.h>
#include <math.h>
class PS
{
    public:
        long tu,mau;

        PS()
        {
            tu=0;
            mau=0;
        }
        ~PS(){};
      int uscln(long a,long b);
      void rutgon();
      void nhap();
      void  xuat();
      PS operator+(PS &a);
      PS operator-(PS &a);
      PS operator*(PS &a);
      PS operator/(PS &a);

};
    int PS::uscln(long a,long b)
    {
        if(a!=0 && b!=0)
        {
            a=abs(a);
            b=abs(b);
            while(a!=b)
            {
                if(a>b)
                    a=a-b;
                else
                    b=b-a;
            }
            return a;
        }
        else
            return 1;
    }

   void PS::rutgon()
    {
        int u;
            u=uscln(tu,mau);
            tu=tu/u;
            mau=mau/u;
    }

    void PS::nhap()
    {
        Nhap:
        cout<<"Nhap tu so ";
        cin>>tu;
        cout<<"Nhap mau so ";
        cin>>mau;
        if(mau==0)
        {
            cout<<"Mau phai khac 0"<<endl;
            goto Nhap;
        }
    }

    void PS::xuat()
    {
            rutgon();
        if(mau<0)
        {mau=-mau; tu=-tu;}
        if(tu==0)
            cout<<"0"<<endl;
        else
            if(mau==1)
                cout<<tu<<endl;
            else
                cout<<tu<<"/"<<mau<<endl;
    }

    PS PS::operator+(PS &a)
    {
        a.tu=tu*a.mau+mau*a.tu;
        a.mau=mau*a.mau;
        return a;
    }
    PS PS::operator-(PS &a)
    {

        a.tu=tu*a.mau-mau*a.tu;
        a.mau=mau*a.mau;
        return a;
    }
    PS PS::operator*(PS &a)
    {
        a.tu=tu*a.tu;
        a.mau=mau*a.mau;
        return a;
    }
    PS PS::operator/(PS &a)
    {
        a.tu=tu*a.mau;
        a.mau=mau*a.tu;
        return a;
    }  

Đăng ký kênh youtube để ủng hộ Cafedev nha các bạn, Thanks you!