THE VARIABLES IN ALZEBRA AND COMPUTER PROGRAM–B
Let us write a computer program
(Remember that a computer program
Simply speaking is a “set of orders “
Given by human engineer to the CPU
And written on the main memory board
After being translated into 010101 code )
Some English words called “reserved words” are also used
They are code names for some basic electric circuits.
Or for complicated mathematical circuits.
Some times even a comma,bracket,full stop etc
Can switch on or switch off a big circuit!
Remember that all instructions
Including such specially meaning punctuation marks
are translated Internally by special computer parts
into the 010101 code intelligible to the CPU.
There is also a very important fact.
From the moment we switched on the computer
The CPU starts sending hundreds or perhaps thousands
Of routine electric pulses to all parts
And only if “all is well” it sends
An “I am ready” message to the human engineer
(When only the MSDOS was in vogue
This “I am ready” message showed up
As the familiar “MSDOS prompt”)
The detailed internal processes
To make itself ready for use by the human engineer
Is called a “boot strap program”
And its meaning is obvious to all.
Then only we can start mathematical work
By typing code word “begin”
Or an equivalent word
(Similarly at the very end of program the word “end”
Or a similar word is to be typed.
It marks the extreme end of the program
And switching of all circuits by CPU).
Nowadays a magnetic copy
Of the entire program from “begin” to “end”
Done by you is invariably kept stored
Or “saved” permanently in magnetic discs
Fixed inside computer itself.
It is in no way connected to main memory
But when required copy of it can be taken
Onto the main memory in a moment’s time!
Outside copies are also taken
And sent by business men to their central office
Otherwise the big banks and business offices
And big government departments
Can not keep watch on their daily work
But in the ancient days of 1940s
No such arrangements were available
Perhaps magnetic tapes could record
Some data under supervision of expert engineers.
Now let us study a simple computer program.
“2). Name four selected memory houses as X, Y, Z, K”
“3).formula is K=X-2Y+5Z”
“4). Give values x=30, y= 20, z=60”
“5).calculate K using above formula”
“6).Print value of k “
Using this program you can get answer
Even for very big values of X,Y and Z
As easily as for small values.