Requirements for Good Software Programming

Before we talk about how a program should be created and develop talking about SDLC i.e
software developement life circle, it is imperative to first of all enlighten ourself on what is a program.
A program is a set of instructions or commands to be executed by the computer to accomplish some task. A program involves code for solving a problem and also good documentation which would be a guideline to anyone who tries to understand the program.
An algorithm is a formula, a method, a recipe, a step by step procedure to be followed in order to obtain the solution to a problem.
Conversion of an algorithm to a program in a programming language following the syntax and semantics of that language is defined as a code.
Syntax is the correct method or grammar of writing a command or series of commands which are pre-defines by that particular programming language. Semantics is the logical meaning of a program or series of commands, separate from the grammatical structure. The computer detects syntax errors but does not detect logical errors.
What are the Criteria for a good program?
It should be flexible enough for the end users
It should be interactive and not boring for the end users
It should be correct i.e. output should be as per the specifications
It should be reliable; it should function accurately for a long period of time and also function correctly over all ranges and combination of data.
It should be robust; unwanted inputs or data should be identified and proper error message should be flashed. It should never crash.
It should be user friendly with enough comments, tips, on-line help and short cut options.
It should be efficient, with minimum memory and quality output in acceptable time span.
It should be readable i.e. it should be simple so that it can be understood to make changes and enhance it if required.
It should be portable so that program can be executed on different machines and environment.
It should follow all standards and have proper documentation.