Everything Is a Number

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From the course by Duke University

Programming Fundamentals

574 ratings

Duke University

Programming Fundamentals

574 ratings

Course 1 of 4 in the Specialization Introduction to Programming in C

Programming is an increasingly important skill, whether you aspire to a career in software development, or in other fields. This course is the first in the specialization Introduction to Programming in C, but its lessons extend to any language you might want to learn. This is because programming is fundamentally about figuring out how to solve a class of problems and writing the algorithm, a clear set of steps to solve any problem in its class. This course will introduce you to a powerful problem-solving process—the Seven Steps—which you can use to solve any programming problem. In this course, you will learn how to develop an algorithm, then progress to reading code and understanding how programming concepts relate to algorithms.

From the lesson

Types

Everything is a number to a computer, but types determine the size and interpretation of numbers. In this module you will learn about types beyond integers, both their conceptual representations, and their hardware representations in binary. You will learn basic data types, "non-number" types, and complex, custom types, as well as some important caveats, so you will avoid type-related programming mistakes.

Everything Is a Number2:48

Meet the Instructors

Andrew D. Hilton
Associate Professor of the Practice
Electrical and Computer Engineering
Genevieve M. Lipp
Adjunct Professor
Electrical and Computer Engineering/Mechanical Engineering
Anne Bracy
Senior Lecturer
Computer Science, Cornell University

You just read about how everything is a number, but let's see how this principle

applies to some things that may not seem like numbers at first glance.

Strings are numbers,

you have seen literal sequences of characters before, such as Hello World!

But did you think about how the computer stores them as numbers?

Each character occupies some of the computer's memory.

We'll talk about exactly how much later, so

you can think of each character conceptually in a box.

In terms of hardware though, the computer stores each character as a number.

You can look up the decimal or hexadecimal values of different characters in an ASCII

table, and you can see the decimal values of these particular characters here.

Of course, the computer stores them as binary numbers.

One fun consequence of computers storing letters as numbers

is that we can do math on them.

This principle underlies most modern methods of cryptography.

Another thing that may not seem to be a number at first is an image,

like this one of some flowers.

This image is made of about a million pixels,

which each numerically represent the colors in the image.

To see these pixels, let's zoom in on this small section of the image.

Here, you can see the image magnified several times.

You can see how this image looks blocky or pixelated.

This is what the image actually looks like if you could look that closely.

Note that if you try this yourself,

you might end up with something that looks much smoother like this.

Most image software will apply algorithms to smooth out the pixelation when you

enlarge an image.

You have to turn that off to see the original pixels.

Let us return to our enlarged image that shows the original pixels more clearly.

If we look only at a subset of this image, and blow it up even further,

we can see and talk about the individual pixels more easily.

Here are 16 pixels from the original image, which had about a million pixels,

just to give you an idea of how much we have zoomed in now.

This dark purple pixel has a red value of 55, a green value of 27,

and a blue value of 75.

Meanwhile, this golden pixel has drastically different RGB values,

166, 136, and 41, giving it an entirely different color.

Sound is another important thing that computers process.

As I'm talking, you can see the waveforms of what I'm saying.

The computer encodes these as numbers and sends them to the sound hardware,

which uses them to determine how to move the speaker generating the desired sound.

There are many other types of data you might want to represent and compute on.

You'll learn about data that is formed from sequences in Course 3.

For now, you're going to learn about structs and typedefs.

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