while (condition) {
// code block to be executed
}

do {
  // code block to be executed
}
while (condition);

void main()
{
   int i = 0;
while (i < 5) 
  {
     cout << i << "\n";
     i++;
  }
}

void main()
{
   int n, a=0;
   cin>>n;
   while( n>0)
   {
      n= n/10;
      a++;
   }
   cout<<a;
}

void main()
{
   int s=0 , a;
   cin>>a;
   while( a!=0)
   {
      s=s+a;
      cin>>a;
   }
   cout<<s;
}
=====================================
int s=0 , a=0;
do
{
cin>>a;
s=s+a;
}while( a!=0);
cout<<s;
return 0;

void main()
{
   int x , s=0,i;
   cin>>x;
   while(x<10)
   {
      i= x % 10;
      x=x / 10;
      s=i+s;
   }
   s=x+s;
   cout<<s;
}

void main()
{
   int x, s=0,i;
   cin>>x;
   while(x<10)
   {
      i= x %10;
      x=x /10;
      s=(i+s)*10;
   }
   s=x+s;
   cout<< s;
}