What is programming
Programming is writing computer code to create a program, to solve a problem. Programs are created to implement algorithms. Algorithms can be represented as pseudocode or a flowchart, and programming is the translation of these into a computer program. To tell a computer to do something, a program must be written to tell it exactly what to do and how to do it. If an algorithm has been designed, the computer program will follow this algorithm, step-by-step, which will tell the computer exactly what it should do.
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What is a programming language
A programming language is an artificial language that a computer understands. The language is made up of series of statements that fit together to form instructions. These instructions tell a computer what to do. There are many different programming languages, some more complicated and complex than others. Among the most popular languages are: Python, Java, C, C++, Javascript. Programming languages are designed to be easy for a human to understand and write in. However, a computer cannot run programs written in these languages directly. Most programming languages have to be translated into machine code before the computer can execute the instructions.
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What is a computer program
Programs are made up of statements that the programming language knows and understands. Just as words are put together to form a sentence, a program puts one or more statements together to form an instruction. Each statement tells the computer to perform a specific task, and the instructions tell a computer what to do. The following sentence asks someone to write a message on a whiteboard: “Please write the words ‘Hello world!’ on the board.” This sentence is an instruction, which contains a single statement. The statement is ‘write the words’. In Python (3.x), the equivalent statement is print.
print("Hello world!")
The following Python (3.x) program contains two instructions, each built up from one statement:
if age >= 15
print("You are old enough to drive a car!")
Consider this simple problem. A cinema is offering discount tickets to anyone who is under 15. Decomposing this problem, gives this algorithm:
1. find out how old the person is
2. if the person is 15 or older than 15 then say “You are not eligible for a discount ticket.”
3. otherwise, say “You are eligible for a discount ticket.”
In pseudocode, the algorithm would look like this:
OUTPUT "How old are you?"
INPUT User inputs their age
STORE the user's input in the age variable
IF age is more than or equal to15
print/show "You are not eligible for a discount."
else
print/show "You are eligible for a discount."
Creating the program in Python
A Python (3.x) program to meet this algorithm would be:
age = int(input("How old are you?"))
if age >= 15
print("You are not eligible for a discount.")
else:
print("You are eligible for a discount.")
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