A number is a number, or to be specific, a digit. This digit(s) can be represented in many different ways and in most cases, you’re going to represent them in base-10(decimal) or base-16(hexadecimal, or simply, hex).

In order to “print”[1] a decimal number(remember, decimal is base-10 or “human-readable number”) we use the %d specifier with printf() function, which means, “Whenever you’ve reached this %d, replace it with a decimal number from the arguments that I’ve passed to you.”, and no worries if you didn’t understand what I just said. Let’s write it done. (GOTO 02)

#include <stdio.h>

int main(int argc, char *argv[]){

  printf("My number is %d.\n", 65);

  return 0;
}

Compile and run:

$ cc -o /tmp/numbers.bin /tmp/numbers.c
$ /tmp/numbers.bin
My number is 65

What if I told you, this very number here(or there) can be represented as a(n alphabet) letter! Or to make it more complicated, telling you that almost all “string”s are made of nothing but numbers![2]

Let’s have a look at how C is handling various type of data:

• char: A character, or the smallest data type, which is 1 byte.
• short: Bigger than a char and must be “at least” 2 bytes.
• int: Basic integer, bigger than short and “at least” 2 bytes.
• long: Bigger than int and “at least” 4 bytes. (Finally! 32-bits! Yes! that is exactly related to your operating system and CPU architecture!)

Think of the data type as “size of a box” which you put your stuff in it.

Numbers can be either signed or unsigned, and by default, when you declare or define your variables, they will be in signed form, which means, they can hold either a negative OR a positive value. Let’s have a look on the supported range of each one: (On a typical x86 machine, of course!)

• char: -127 to +127
• unsigned char: 0 to +255
• short: −32,767 to +32,767
• unsigned short: 0 to +65535
• int: −32,767 to +32,767
• unsigned int: 0 to +65535 (Yeah, WTF!)
• long: −2,147,483,647 to +2,147,483,647
• unsigned long: 0 to 4,294,967,295

If you’re confused about some of these values, repeat with me:

“Nothing is true, everything is permitted.”

The C standard(s) are only defining sort of an order[3]ing on how this data types are related to each other:

char < short < int < long < long long

And it means “a char is smaller than a short, which is smaller than an int, which is smaller than a long, which is smaller than a long long.” :)

Enough for now! Change that 65 dude to some other values and see how your code will behave, and whenever you’re done, a new blog post will be automagically created for you! (By the power of “When the pupil is ready to learn, a teacher will appear.”)

Check this link to confuse yourself even more: https://en.wikipedia.org/wiki/C_data_types (Yeah, go ahead!)

[1] Means “displaying on the screen” or shell or terminal window.

[2] Even if your favorite language has implemented them with blackjack and hookers(std::string), under the hood, they’re still the same cool old ASCII digits. https://www.youtube.com/watch?v=5l3ipKcnYlQ

[3] Out of the chaos.