Introduction to Programming Language
A program is a set of instructions that tells a computer what to do in order to come up with
a solution to a particular problem. Programs are written using a programming language.
A programming language is a formal language designed to communicate instructions to a
computer. There are two major types of programming languages:
2. high-level languages.
Low-Level Languages
Low-level languages are referred to as 'low' because they are very close to how different
hardware elements of a computer actually communicate with each other. Low-level
languages are machine-oriented and require extensive knowledge of computer hardware
and its configuration. There are two categories of low-level languages: machine language
and assembly language.
Machine language, or machine code, is the only language that is directly understood by the
computer, and it does not need to be translated. All instructions use binary notation and are
written as a string of 1s and 0s. A program instruction in machine language may look
something like this:
However, binary notation is very difficult for humans to understand. This is where assembly
languages come in.
An assembly language is the first step to improve programming structure and make
machine language more readable by humans. An assembly language consists of a set of
symbols and letters. A translator is required to translate the assembly language to machine
language called the 'assembler.'
While easier than machine code, assembly languages are still pretty difficult to understand.
This is why high-level languages have been developed.
High-Level Languages
A high-level language is a programming language that uses English and mathematical
symbols, like +, -, %, and many others, in its instructions. When using the term 'programming
languages,' most people are actually referring to high-level languages. High-level languages
are the languages most often used by programmers to write programs. Examples of high-
level languages are C++, Fortran, Java, and Python.
Learning a high-level language is not unlike learning another human language - you need to
learn vocabulary and grammar so you can make sentences. To learn a programming
language, you need to learn commands, syntax, and logic, which correspond closely to
vocabulary and grammar.
The code of most high-level languages is portable and the same code can run on different
hardware without modification. Both machine code and assembly languages are hardware
10101011100001110100111101
specific which means that the machine code used to run a program on one specific
the computer needs to be modified to run on another computer.
A high-level language cannot be understood directly by a computer, and it needs to be
translated into machine code. There are two ways to do this, and they are related to how
the program is executed: a high-level language can be compiled or interpreted.
Compiler vs Interpreter
A compiler is a computer program that translates a program written in a high-level language
to the machine language of a computer.
The high-level program is referred to as 'the source code.' The compiler is used to translate
source code into machine code or compiled code. This does not yet use any of the input
data. When the compiled code is executed, referred to as 'running the program,' the
program processes the input data to produce the desired output.
An interpreter is a computer program that directly executes instructions written in
a programming language, without requiring them previously to have been compiled into
a machine language program.
A little about the C++ language
C++ is a cross-platform language that can be used to create high-performance applications.
It was developed by Bjarne Stroustrup, as an extension to the C language. The language was
updated 3 major times in 2011, 2014, and 2017 to C++11, C++14, and C++17.
Why Use C++?
1. C++ is one of the world's most popular programming languages.
2. C++ can be found in today's operating systems, Graphical User Interfaces, and
embedded systems.
3. C++ is an object-oriented programming language that gives a clear structure to
programs and allows code to be reused, lowering development costs.
4. C++ is portable and can be used to develop applications that can be adapted to
multiple platforms.
5. C++ is fun and easy to learn!
6. As C++ is close to C# and Java, it makes it easy for programmers to switch to C++ or
vice versa.
How to start writing programs?
Algorithm
The algorithm is a step-by-step procedure, which defines a set of instructions to be executed in
a certain order to get the desired output. Algorithms are generally created independent of
underlying languages, i.e. an algorithm can be implemented in more than one programming
language.
Qualities of a good algorithm
1. Input and output should be defined precisely.
2. Each step in the algorithm should be clear and unambiguous.
3. An algoƌiƚhm ƐhoƵldn͛ƚ inclƵde compƵƚeƌ code͘ InƐƚead͕ ƚhe algoƌiƚhm ƐhoƵld be
written in such a way that it can be used in different programming languages.
Good, logical programming is developed through good pre-code planning and
organization. This is assisted by the use of pseudocode and program flowcharts.
Flowcharts
Flowcharts are written with program flow from the top of a page to the bottom. Each
command is placed in a box of the appropriate shape, and arrows are used to direct
program flow. The following shapes are often used in flowcharts:
Pseudocode
Pseudocode is a method of describing computer algorithms using a combination of
natural language and programming language. It is essentially an intermittent step towards
the development of the actual code. It allows the programmer to formulate their thoughts
on the organization and sequence of a computer algorithm without the need for actually
following the exact coding syntax.
Examples –
Ques1. Write pseudocode for finding the sum of 2 numbers.
Pseudocode
1. Start
2. Input 2 numbers ʹ number1 and number2
3. Add number1 and number2 to find sum
4. Print sum
5. End
Ques2. Write pseudocode to find the area of a square.
Pseudocode
1. Start
2. Input length of the square
3. Calculate the area of the square as length * length
4. Print area
5. End
Ques3. Write pseudocode to find simple interest.
Pseudocode
1. Start
2. Input a principal as P, rate as R, and time as T
3. Calculate simple interest as P * R * T
4. Print simple interest
5. End
Ques4. Write pseudocode to convert temperature from
Fahrenheit (°F) to Celsius (°C).
Pseudocode
1. Start
2. Read temperature in Fahrenheit
3. Calculate temperature with formula C=5/9*(F-32)
4. Print C
5. End
Ques5. Write pseudocode to check if a number is odd or even.
Pseudocode
1. Start
2. Input a number
3. If remainder, when number is divided, is 0, print ͞Even number͟
4. Else print ͞Even number͟
5. End
Ques6. Write pseudocode to find the max of 3 numbers.
Pseudocode
1. Start
2. Read three numbers ʹ a,b and c
3. Compare a and b, if a > b
Compare a and c, if a > c
Print a
Else
Print c
Else
Compare b and c, if b > c
Print b
Else
Print c
4. End
Ques7. Write pseudocode to find the sum of n natural
numbers.
Pseudocode
1. Start
2. Read a number n
3. Repeat the following till n becomes equal to 0
Add n in sum
Decrement n
4. Print sum
5. End
Ques8. Write pseudocode to find the factorial of a number.
Pseudocode
1. Start
2. Read a number n
3. Initialise m =1
4. Repeat the following till m becomes equal to n
Multiply m with factorial
Increment m
5. Print factorial
6. End
Ques9. Write pseudocode to find if a number is prime or not.
Pseudocode
1. Start
2. Read a number n
3. Initialise divisor = 2
4. Repeat till divisor < n
If n is divisible by the divisor
Print ͞Non-Prime͟
End
Else
divisor = divisor + 1
5. Print ͞Prime͟
6. End
Ques10. Write pseudocode to print all prime numbers till n.
Pseudocode
1. Start
2. Read a number n
3. Initialise num = 2
4. While num <= n do
Initialise div = 2
While div < num do
If n is divisible by div
num = num + 1
Else
div = div + 1
print num
num = num + 1
5. End
Brain Teasers
1. You are standing outside of a room with no windows. The room has three
light bulbs and three switches outside of the room. Each switch controls
one of the light bulbs. You may only enter the room one time. How can
you find out what switch goes to each light bulb?
Solution
To find out what switch goes to what light bulb, you could turn on the
first switch and wait five minutes.
After five minutes have passed, turn off the first switch and turn on the
second switch.
Look for the warm light bulb when you walk back into the room.
The light that is on goes to the second switch, the warm light bulb goes to
the first switch and the last light bulb goes to the third switch.
2. You have a 3-gallon jug and 5-gallon jug, how do you measure out
exactly 4 gallons?
Solution
First, fill the 3-gallon jug. Then pour the 3 gallons into the 5-gallon jug.
Now the 3-gallon jug is empty, and the 5-gallon jug has 3 gallons in it.
Fill the 3-gallon jug again and pour it into the 5-gallon jug. Only 2 gallons will fit
because it already has 3. Exactly 1 gallon is left in the 3-gallon jug.
Dump out the 5-gallon jug.
Pour your 1 gallon into the 5-gallon jug. Fill up the 3-gallon jug one more time
and pour it into the 5-gallon jug. You have exactly 4 gallons!
3. You͛re about to get on a plane to Seattle. You want to know if it͛s raining.
You call 3 random friends who live there and ask each if it͛s raining. Each
friend has a 2/3 chance of telling you the truth and a 1/3 chance of
messing with you by lying. All 3 friends tell you that ͞Yes͟ it is raining.
What is the probability that it͛s actually raining in Seattle?
Solution
You only need 1 of your friends to be telling the truth for it to be raining in
Seattle.
It͛s fastest just to calculate the odds that all ϯ are lying, and it͛s not raining.
Each friend has a ϭͬϯ chance of lying. Multiply the odds together... you get 1/27
(1/3 * 1/3 * 1/3).
So 1/27 is the probability that all 3 friends lied at the same time.
The probability that at least 1 told you the truth? 26/27 or around 96% that
it͛s raining in Seattle.
Copywrite claim by CODEHOVER https://makhdoomusman.blogspot.com/2021/10/introduction-to-programming-language.html