0. Introduction

A program is a set of commands which are designed to be run by a computer.

These commands must be written in a language that the computer can understand.

But languages that computers understand are difficult for humans, because they differ very much from spoken human languages. Writing programs in "machine code" is hard: creating the program is very error-prone and correcting (or improving) it is very time-consuming.

For example, a program which stores a value "2" at the memory location 1, using a simple 80s computer, based on a Z80 8-bit processor, would look like this:

0011 1110 0000 0010 0011 1010 0001 0000

Almost illegible. That’s the reason why the most commonly used languages are similar to human language. These are called "high-level languages." Typically, they are very similar to English language, but they follow stricter rules.

Index

• Why?
• 0. Introduction
• 0.1 High-level and low-level languages
• 0.2. Assemblers, compilers and interpreters
• 0.3. Pseudocode
• 0. Suggested exercises
• 1. First contact with C#
• 1.1 Display a text using C#
• 1.2. How to test this program using Mono
• 1.3. Display integer numbers on screen
• 1.4. Basic mathematical operations in C#
• 1.5. Introduction to variables: int
• 1.6. Identifiers
• 1.7. Comments
• 1.8. User-entered data: ReadLine
• 2.1. Conditional statements
• 2.1.2. "if" and compound statements
• 2.1.3. Relational operators
• 2.1.4. if-else
• 2.1.5. Logical operators: &&, ||, !
• 2.1.6. The risk of assignment inside an "if"
• 2.1.7. Introduction to Flowcharts
• 2.1.8. Conditional operator: ?
• 2.1.9. switch
• 2.2. Iteration statements
• 2.2.1. while
• 2.2.2. do ... while
• 2.2.3. for
• 2.3. Exiting a loop: "break" command
• 2.4. "Continue" statement: force the next iteration
• 2.4b. Solved exercises with "for"
• 2.5. The "goto" statement
• 2.6. More on flowcharts. Box (Chapin) diagrams.

(More coming soon)

Why?

This text is an introduction to computer programming using C# language.

It is organized in a slightly different way compared to "conventional" text books: I tried to include practical exercises as soon as possible, to try ti avoid an excess of theory which might make the text harder to read.

This text was written by Nacho Cabanes. If you want to get the latest PDF version, you can find it on my website:

http://www.nachocabanes.com/english/

This text is freely available ("for free"). You can download it and distribute to others, provided the text is not altered and credits are given.

This text is distributed "as is" without warranty of any kind. But I want it to be useful, so please report any errors you might find. Also, English is not my native language, so there might be translation errors. I would be glad to know about them, so that I can correct them.

For any suggestions, feel free to post a comment on this blog.