Programming Variables

 A variable is an element of a Computer Program. Computers Programs are stored in Computer memory. Computer memory is also the seat of Program variables. Variables stored in Computer memory can be identified. The name given to the variable is the identifier of the variable. This identifier helps to identify the variable.

A Program variable is very much useful. Computer Programmers use variables meaningfully and purposefully. Variables dish out data to Program instructions. Instructions of a Computer Program are able to use variables quite effectively. 

A value that is acquired by a Program variable is used by Program instruction. Whenever a variable is encountered by a Program instruction, a simple substitution occurs. The variable is substituted by the value. This is how processing of data is helped.

Let us see how we have to play with variables used in a Computer Program:

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Integer x, y

x = 4

y = 5

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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

//x and y are variables 

//These variables can acquire values

//The acquired values are integers

//Only integers can be acquired 

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The variable is substituted by a value that has earlier been acquired. We can easily recall that the variable has been given a certain value. 

It is important to note that a variable that dangles ( simply hangs ) is not usable. Unless and until a value is properly acquired by a variable, use of the variable is a serious mistake. Yes, it's a mistake on the part of a Programmer to use a variable that has nothing inside ( no value).  

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Integer p, q, r;

p = 9;

r = p + q //Error!

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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Note: Use of 'p' is fine, but still no value has been acquired by 'q'. 'q' simply hangs and its state is somewhat undefined. So, we have to correct ourselves from using a variable lying in an undefined state.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

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Note: Many times beginners use a variable that is not associated with a proper value.

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We have to always keep in mind that a variable can acquire only a proper value. So, a Computer Programmer has to be very alert in this respect. 

It is emphasised that only a proper value that is in tune is acquired by a Program variable. An attuned value is approved by a Computer. So, those new to the Programming world have to be very careful. They are specially recommended to  note this piece of advice.

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Goodbye! 

Have a great day!!

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