How's a computer programmed?

Question

in plain English, please, as I am a postman, not IT person :-)

Answer 1

Basically, your processor is hard coded with a series of instructions like add, multiply, divide, read memory and write memory. Programs are lists of instructions that are executed in order. It's simple number manipulation and mathematical principles rolled together to create this illusion of a sentient program helping you do work.

Answer 2

Humans write in programming languages which are relatively easy to read. each line of code is called an instruction. When a complete list of instructions are put together you have a program which is then compiled into a language only the computer understands

Now a program is almost like an instruction book for assembling something. In programs you have a main line of code and two features called SubRoutines and Functions.

The Main line can be thought of as the task at hand, in this case, lets build something from the store (like a bookcase which comes in a flat box, I call them flat-box specials)

Think of a subroutine as a part of the instruction book which is repetitive, like maybe TightenTheScrew--No value is returned, only a task is complete. No matter what, you will ALWAYS tighten a screw the same way.

A function is much like a subroutine, but it returns a value back to the main line of the program. So you can think of a function as GetScrewNumber(2)......where you retrieve a value (A screw, the 2 in the parenthesis is a value passed into the function...so we get screw number 2) from the parts pile and return it to the item you are building

So really, it is just a set of instructions telling the computer how to complete a task, which in simplest of programs, may be to write a phrase to the screen.

Answer 3

A program is basically a list of commands that the computer knows, and the programmer lists them in certain orders to manipulate memory, files, data, etc. The actual code is a long series of binary octets (8 digit numbers like 10110010) that represent different things. It is actually possible to code in these digits, but modern programming languages allow programmers to use a more "english" based approach like:
if a = 1 then print "hi"
if a = 2 then print "bye"
Although the above "code" isnt an actual representation of a program, it should give you the idea of the type of things a program might do.

Answer 4

A computer is generally programmed through the issuance of a sequence of instructions in a languange that the computer understands, called machine language.

It is difficult to program in machine language, so higher level languages were developed to give people a more readable/understandable language to program in. Those higher level languages are then translated by a compiler or interpereter into machine language, so the computer can run the program.

Computers have a specific instruction set, which is essentially the words and actions it understands. That instruction set can be manipulated through programming to make computers do what you see them do, like show pictures or type documents.

Answer 5

Using one or more of many computer languages. There are countless. Big ones include C, C++, C#, Perl, Python, Java, Ruby, VB.NET, and so on.

You write code as per the computer language of your choice. Once done with your code, you go through the appropriate steps to make this code usable by the computer. For languages like C and C++, this is compilation, where it is translated from code humans can read to what the computer processor can understand. Other languages have other steps or requirements.