Programming Fundamentals

Table Of Content

Description

Algorithms are designed to solve a problem but cannot be directly implemented by the computer. A computer can only execute machine language instructions. Machine language instruction in binary coded language can be easily executed. To remember codes for different operations of a machine language is highly difficult. Thus, high-level languages can be used to implement algorithms. A compiler is software which converts a high level language to machine language. It converts the source program to object program.

High-Level language Translation

This can be shown by a diagram as follows:

Basic Programming language Preliminaries

Any programming language is divided into two distinct parts. These parts are described as:-

• Syntax – They are the rules which are to be followed to form structures which are grammatically correct with respect to the programming language used.
• Semantics – It assigns meanings to syntactic structures.

Writing basic programs

Writing a program to find area of a circle would be as

Formula to calculate Area of a circle is,

A = Πr2

Where r = radius of the circle

In ‘C’ language, multiplication operator is ‘* ’
Therefore Area (A)

A = Π * r * r      ….. (1)

Eqn (1) is called an Arithmetic statement in programming terminology

‘A ‘and ‘r’ are variables, values ‘Π ’ is a constant value 3.14.

Before execution (memory location)

After Execution

Program:

void main (  )
{
unit r; A
float A;
r = 1;
A = 3.14 * r * r;
}

To read and understand the program, comments are used. It describes the program.

a) Single line comment
b) Multiple line comment

a) Single-line Comment – It is preceded by double slash ( // ) and cannot exceed a line

Example: –

int a;         // declaration of an integer

b) Multi-line Comment – It consists of sequence of characters beginning with a forward slash ‘/’ asterisk combination (/*) that is treated as a single whitespace character by the compiler else it is ignored. It can inclined any combination of characters even ‘/n ‘excluding delimiter (*/).One should note that comments cannot be nested.

Example:-

/* Comments can also be given like this */.