It is advisable to use container classes of the STL so that you don’t have to go through the pain of writing the entire code for handling collisions, making sure its working well, testing it repeatedly with an overhead of time consumption.

Suppose you have some data that has values associated with strings and its fields consist of grades> in this situation you can directly use hash table instead of having it created by yourself.

A class is said to be a container class which is utilized for the purpose of holding objects in memory or persistent media. A generic class plays a role of generic holder. A container class is a good blend of predefined behavior and an interface that is well known. The purpose of container class is to hide the topology for the purpose of objects list maintenance in memory. A container class is known as heterogeneous container, when it contains a set of different objects. A container class is known as homogeneous container when it contains a set of similar objects.

SELECT  * from Employees  WHERE  upper(EmpName) like upper('joe%');

Copper in 4 kg = 4/5 kg          and      Zinc in 4 kg = 4 x (4/5) kg

Copper in 5 kg = 5/6 kg          and      Zinc in 5 kg = 5 x (5/6) kg

Therefore, Copper in mixture = 45+56=4930 kg

and  Zinc in the mixture = 165+256=22130kg

Therefore the required ratio = 49 : 221

Here the ratio of mixtures( i.e milk , water) doesnot matter. But the important point is that whether the total amount ( either pure or mixture ) being transferred is equal or not.Since the total amount ( i.e 5 cups) being transferred from each one to another , hence A =B.

Assume the weight of alloy a is 100 kg 

Therefore, The weight of alloy B is 400kg

             Gold          silver         copper

    A       40kg          60kg          0kg

    B      140kg         160kg        100kg

  total    180kg          220kg        100kg

Therefore, Ratio of gold and silver in new alloy = 180500:200500= 36% :44%

Let quantity of mixture be x liters.

Suppose a container contains x units of liquid from which y units are taken out and replaced by Water. After operations , the quantity of pure liquid = x1-yxn units, Where n = no of operations . 

So, Quantity of Milk = x1-6x2  

Given that, Milk : Water = 9 : 16 

=> Milk : (Milk + Water) = 9 : (9+16)

=> Milk : Mixture = 9 : 25 

 Therefore, x1-6x2x=925

=> x = 15 liters

pool : kerosene 

   3  :  2(initially) 

   2  :  3(after replacement)

 Remaining QuantityInitial Quantity=1-Replaced QuantityTotal Quantity

(for petrol)   23=1-10k

 => K = 30

 Therefore the total quantity of the mixture in the container is 30 liters.