A program is set of instructions that help us to perform a task in a machine. A simple example would adding two numbers. The machine can be a computer, calculator or other embedded device. Programs are mostly written using high level languages. High level languages includes C, C++, Java, Objective-C and so on.

Programs are everywhere. You can find programs used in all tasks from a simple text messaging to complex space missions. When you using a computer or a mobile, you are actually running a program or multiple program. Programs can be a simple addition or the complex operating systems.

There are hundreds of programming languages and most of them wont know even the names of all of them. Do you need to know all of them? Obviously not. You just need to know one or two based on your need.


In programming language, we often refer an instruction or a line of code as statements. In order to differentiate between multiple instructions, each language use its own way to terminate a statement. In languages like C, C++ and Objective-C, semi-colon is used for terminating each instruction. Multiple lines may be used for a single statement for readability.

Code Block

In languages like C, C++ and Objective-C, we often use { and } for start and end of code blocks respectively. All variables declared with a code block are local and accessible within the block only.