Table of Contents

• Includes
  • stdio.h
  • stdbool.h
  • math.h
• Strings and Variables
  • Strings
  • Variables
  • Integers
• Functions
  • Basic Functions
    • printf
    • scanf
• Useage of the Funtions
  • Basic useage
    • printf()

Includes

stdio.h

This is needed for the printf and scanf functions

#include <stdio.h>

stdbool.h

This is needed for the bool type

#include <stdbool.h>

math.h

This is needed for the math functions (sqrt, pow, etc.)

#include <math.h>

Strings and Variables

Strings

In Python we would do this:

string = "Hello"

That would create a string with a value of "Hello". In C we have to do it a bit differently. Strings are a sequence of characters.
They are declared like this:

char string[10];

this creates a string with a length of 10 characters. Which we can later use to assign a value to.
You can also initialize it with a value like this:

char string[10] = "Hello";

This creates a string with a length of 10 characters and a value of "Hello".
You can also do this:

char string[] = "Hello";

This creates a string with a length of 6 characters and a value of "Hello".
The length is 6 because the compiler automatically adds a null character at the end of the string.

Variables

Variables are used to store values.
They are declared like this:

int x;

This creates an integer variable called x.
You can also initialize it with a value like this:

int x = 5;

This creates an integer variable called x with a value of 5.
You can also do this:

int x;
x = 5;

This creates an integer variable called x and thn later set the value to 5.

Integers

Integers are whole numbers.
They are declared like this:

int x;

This creates an integer variable called x.
You can also initialize it with a value like this:

int x = 5;

This creates an integer variable called x with a value of 5.
You can also do this:

int x;
x = 5;

This creates an integer variable called x and thn later set the value to 5.

Functions

Basic Functions

printf

This function is used to print text to the console. It is declared like this:

printf("Hello World!"); // This prints "Hello World!" to the console

scanf

This one is to get input from the user, just like input() from python. It is declared like this:

int x; //We define the variable x first because scanf needs a variable to store the input
scanf("%d", &x); // This gets input from the user and stores it in x

Formats for scanf

To get thn set the data taken from scanf we need to do something like this:

scanf("%format", data);

here the type is the format for example "d" is for int, so if the data we get the from the user is to be handle as an integar we use scanf("%d", data) this will make so the data is stored as an int.
Like so for each datatype the format is different and needs to be defined. The formats are as follows:

Data Type	Size (bytes)	Format Specifier
int	4	%d
char	1	%c
float	4	%f
double	8	%lf

In Python we wouldn't use format nor define the variable and its datatype rather do this:

x = input()

The compiler would do it by itself.
But in C we have to define the variable first and then use scanf to get the input and store it in the variable.

Useage of the Funtions

Basic useage

printf()

As we know this is to show the user something, like greetings and such. But to show data like strings or variables we need to use the same format thing like scanf().
Lets say we have a integar stored in the variable named age, and we want to print that. For python we would just do print(age), this would tell the compiler that its a value of somesort. But for C we need cant do that, rather we would have to do this:

printf("%d", age);

This will tell the compiler that age is a int, and that will print the value. And we use the format defined in the scanf for the datatypes accordingly.
We can user multiple data like this, as well multiple datatypes:

// The ";" is important after each line
char name[] = "name";
int age = 20;

printf("%c %d", name, age);

The output would be: name 20

printf("Name: %c \nAge: %d", name, age); // The \n is to go to a new line

The output would be:
Name: name
Age: 20