If...else statement to switch...case statement

Dalam bab ni kitorang belajar camne nak tukar if...else statement kepada switch...case statement.
kat bawah ni ialah contoh camne nak buat statement ni...(kalau tak faham,buat2 faham jer...hehehe).

#include<iostream.h>
main()
{
//declare variable
  int age;
//if else statement
  if(age>=1 ll age<=6)
    {cout<<"you are kids!;}
  else if(age>=7 ll age<=12)
    {cout<<"you are child babe!";}
  else if(age>=13 ll age <=21)
    {cout<<"you are teenager!";}
  else if(age>=21 ll age<=30)
    {cout<<"you are adult now!";}
  else if(age>=30)
    {cout<<"you are old,boo!";}
  else
    {cout<<"invalid selection";}
  return 0;
}

*yg kat atas ni ialah if...else statement dan yang kat bawah ni pulak ialah switch...case statement.

#include<iostream.h>
main()
{
  //declare variable
    int age;
  //input
    cout<<"enter your age=";
    cin>>age;
  //switch case statement
    switch(age)
    {case('age'>=1 ll 'age'<=6):cout<<"you are kids!";break;
      case('age'>=7 ll 'age'<=12):cout<<"you are child beb!";break;
      case('age'>=13 ll 'age'<=21):cout<<"you are teenage!";break;
      case('age'>=22 ll 'age'<=30):cout<<"you are adult now!";break;
      case('age'>=30):cout<<"you are old!";break;
      default:cout<<"invalid selection";
     }
  return 0;
}