Code Corner

C Windows Setup

Download the GCC Compiler

Download and extract the last GCC POSIX version compiler for windows.

Set the binaries path in the environment variables.

C:\mingw64\bin

WinLibs

WinLibs - MinGW-w64 personal build = GCC for Windows 32-bit and 64-bit - Coming soon: the largest collection of open source libraries ported to Windows using MinGW-w64 and MSYS2.

https://winlibs.com/#download-release

C Linux Setup

Ensure GCC is installed

Make sure your Linux distribution have GCC installed

gcc -v

If GCC isn't installed, run the following command from the terminal window to update the Ubuntu

sudo apt-get update

Next install the GNU compiler tools and the GDB debugger with this command:

sudo apt-get install build-essential gdb

VSCode Setup

Download Code Runner and C++ extension pack from VSCode extensions.

Create and open a C HelloWorld.c File in any folder.

Go to Terminal and select Configure Default Build Task.

Select the compiler.

In Windows select C/C++: gcc.exe build active file:

In Linux select g++ build and debug active file:

Basic Hello World starting code

#include <stdio.h>

int main() {
    printf("Hello World");
}

C Variable Declaration

Variable Declaration

In C, a variable declaration consists of the following parts:

Data Type: Specifies the type of data the variable can hold. Examples include int, float, char, and user-defined types.

Variable Name: The name of the variable, which is used to identify and access it in the program. Variable names must follow certain rules:

Must start with a letter (uppercase or lowercase) or underscore (_).
Can contain letters, digits, and underscores.
Case-sensitive.

Semicolon (;): A statement in C ends with a semicolon, including variable declarations.

Example Variable Declarations

Here are some examples of variable declarations:

Data Type	Variable Name	Declaration
`int`	`age`	`int age;`
`float`	`pi`	`float pi;`
`char`	`initial`	`char initial;`
`double`	`price`	`double price;`

Variable Initialization

Initialization is the process of assigning an initial value to a variable at the time of declaration. In C, you can initialize a variable when you declare it by using the assignment operator (=).

Example Variable Initializations

Here are some examples of variable declarations with initialization:

Data Type	Variable Name	Initialization
`int`	`count`	`int count = 0;`
`float`	`temperature`	`float temperature = 98.6;`
`char`	`grade`	`char grade = 'A';`
`double`	`balance`	`double balance = 1000.0;`

Rules and Tips

Variables should be declared and initialized before they are used in your program.

Uninitialized variables contain garbage values.

Local variables (inside functions) are not automatically initialized, so it's essential to initialize them explicitly.

Global variables (outside functions) are initialized to zero by default.

C Data Types and Format Specifiers

Basic Data Types

C provides several basic data types, which can be categorized into the following groups:

Integer Types: Used for storing whole numbers.

Floating-Point Types: Used for storing numbers with a fractional part.

Character Types: Used for storing individual characters.

Void Type: Represents the absence of a value.

Integer Types

Integer data types are used for representing whole numbers (positive and negative) without a fractional part.

Data Type	Description	Range	Format Specifier
`int`	Standard integer type	-32,768 to 32,767 (at least)	`%d`
`short`	Short integer	-32,768 to 32,767 (at least)	`%hd`
`long`	Long integer	-2,147,483,648 to 2,147,483,647 (at least)	`%ld`
`long long`	Long long integer	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 (at least)	`%lld`
`unsigned int`	Unsigned integer	0 to 65,535 (at least)	`%u`

Floating-Point Types

Floating-point data types are used for representing real numbers with fractional parts.

Data Type	Description	Format Specifier
`float`	Single-precision float	`%f`
`double`	Double-precision float	`%lf`
`long double`	Extended-precision float	`%Lf`

Character Types

Character data types are used for representing individual characters.

Data Type	Description	Format Specifier
`char`	Character (1 byte)	`%c`
`signed char`	Signed character	`%c`
`unsigned char`	Unsigned character	`%c`

Void Type

The void type is used to indicate the absence of a specific type. It's often used in functions that don't return a value or for generic pointers.

Data Type	Description	Example Declaration	Format Specifier
`void`	Void (no value)	`void displayMessage();`	N/A
`void*`	Generic pointer	`void* dataPtr;`	N/A

C Arithmetic Operators

Arithmetic operators in C are used to perform mathematical operations on variables and constants.

Basic Arithmetic Operators

C provides several basic arithmetic operators that can be used with numeric data types. Here are the common arithmetic operators along with their symbols:

Operator	Description	Symbol	Example
Addition	Adds two operands	`+`	`result = x + y;`
Subtraction	Subtracts right operand from the left	`-`	`result = x - y;`
Multiplication	Multiplies two operands	`*`	`result = x * y;`
Division	Divides left operand by the right	`/`	`result = x / y;`
Modulus	Computes the remainder after division	`%`	`result = x % y;`

Division Operator - Caveats and Considerations

While division is a common mathematical operation, there are some important considerations to keep in mind when using this operator in C programs.

Division by Zero

One of the most critical caveats in C division is dividing by zero. When you attempt to divide by zero, it results in undefined behavior, and your program may crash or produce unexpected results.

Example	Description	Result
`x / 0`	Division by zero	Undefined
`0 / 0`	Zero divided by zero	Undefined
`5 / 0`	Non-zero divided by zero	Undefined

To prevent division by zero errors, it's essential to check the divisor before performing the division operation.

if (divisor != 0) {
    result = dividend / divisor;
} else {
    // Handle the error or report it
}

Integer Division

Another important consideration is integer division. When you divide two integers using the division operator, the result will also be an integer, and any fractional part is truncated (discarded). This behavior can lead to unexpected results if not handled correctly.

Example	Description	Result
`5 / 2`	Integer division	Result: 2
`7 / 3`	Integer division	Result: 2

To obtain a floating-point result from integer division, you can cast one or both operands to a floating-point type before the division.

float result = dividend / (float)divisor;

Assignment Operators

Assignment operators are used to assign the result of an operation to a variable. They combine an arithmetic operation with assignment.

Operator	Description	Symbol	Example
Assignment	Assigns the value of the right operand to the left	`=`	`x = 5;`
Addition Assignment	Adds the right operand to the left and assigns the result	`+=`	`x += 3;` (Equivalent to `x = x + 3;`)
Subtraction Assignment	Subtracts the right operand from the left and assigns the result	`-=`	`x -= 2;` (Equivalent to `x = x - 2;`)
Multiplication Assignment	Multiplies the left by the right and assigns the result	`*=`	`x = 4;` (Equivalent to `x = x 4;`)
Division Assignment	Divides the left by the right and assigns the result	`/=`	`x /= 2;` (Equivalent to `x = x / 2;`)
Modulus Assignment	Computes the remainder after division and assigns the result	`%=`	`x %= 3;` (Equivalent to `x = x % 3;`)

Increment and Decrement Operators

Increment and decrement operators are used to increase or decrease the value of a variable by 1.

Operator	Description	Symbol	Example
Increment	Increases the operand by 1	`++`	`x++;`
Decrement	Decreases the operand by 1	`--`	`y--;`