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Program
A well-defined set of instructions given to the computer is called
program. A person who develops program is called
programmer.The program has an executable form that the computer can use directly to execute the instructions. The same program in its human-readable source code form, enables a programmer to study and develop the algorithm. Because the instructions can be carried out in different types of computers, a single set of source instructions converts to machine instructions according to the
central processing unit type.
Programming language
A set of words and symbols used to write programs is called
programming language. A programming language is a mean of communication between a user and computer.
Types of programming languages
Ther are two Types of programming languages:
- Low level language
- High level language
Low level language
Low level languages are near to computer hardware and far from human languages.
There are two types of low level languages:
Machine language
In machine language instructions are written in
binary form as
0 or 1. This is the only language that is directly understood by computer.
Assembly language
In assembly language machine instructions are replaced with English like words. It is one step higher than machine language.
High level language
A type of language that close to human languages are called
high level language. The instructions in these languages are similar to English language such as printf and input etc. these languages are easy to understand. Every high level language defines a set of rules for writing programs called
syntax. Each instruction must be written according to the syntax of the language.
Object code
A program in machine language is called object code. It is also called object
program or machine code.
Source code
A program written in a high level language is called
source code. Source code also called
source program.it must be converted into
object code before execution.
Compiler
Compiler is a program that convers the instructions of high level language into machine language as a whole. The compiler checks each statement in the source program and generates
machine instructions. Compiler also checks syntax error in
source program. A source program containing any error
cannot be compiled.
