Fundamentals of C Programming Language

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Table of Contents

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1. Introduction to C
2. C Programming Environment
3. Basic Syntax and Structure
4. Variables, Data Types, and Operators
5. Control Structures
6. Functions in C

Introduction to C

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C is a high-performance, general-purpose programming language that was developed by Dennis Ritchie between 1969 and 1973. It was initially used for systems programming and has since become one of the most widely used languages in the world.

Key Features of C

• Portable: C code can be compiled on any platform that supports the C compiler.
• Efficient: C is a low-level language, which means it provides direct access to hardware resources.
• Flexible: C can be used for systems programming, game development, and even scripting.

C Programming Environment

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To write C programs, you need a few essential tools:

1. Text Editor

A text editor is where you’ll write your C code. Popular choices include:

• Notepad (Windows)
• TextEdit (Mac OS X)
• Sublime Text (Cross-platform)

2. Compiler

The compiler converts your C code into machine code that the computer’s processor can execute. Popular compilers include:

• GCC (GNU Compiler Collection) for Linux, macOS, and Windows
• Microsoft Visual Studio for Windows

3. Debugger

A debugger helps you identify and fix errors in your code.

Basic Syntax and Structure

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C code is organized into functions, which are the building blocks of a program. Here’s a basic example:

#include <stdio.h>

int main() {
printf("Hello, World!\n");
return 0;
}

Key Components

• Comments: // and /* */ are used for comments.
• Variables: Variables store data in memory. They can be assigned a value using the assignment operator (=).
• Data Types: C has several built-in data types, including:

• Integers (int)
• Floating-point numbers (float, double)
• Characters (char)

Variables, Data Types, and Operators

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Variables

Variables store data in memory. Here’s an example of declaring a variable:

int x; // Declare an integer variable named x

You can assign a value to the variable using the assignment operator (=):

x = 10; // Assign the value 10 to x

Data Types

C has several built-in data types, including:

Data Type	Description
int	Whole numbers (e.g., 1, 2, 3)
float	Decimal numbers (e.g., 3.14, -0.5)
double	Double-precision decimal numbers (e.g., 3.14159265359)
char	Single characters (e.g., ‘A’, ‘a’)

Operators

C supports several operators for performing arithmetic operations:

Operator	Description
+	Addition
-	Subtraction
*	Multiplication
/	Division
%	Modulus (remainder)

Control Structures

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Control structures determine the flow of a program’s execution. C supports several control structures, including:

1. Conditional Statements

Conditional statements use conditions to determine whether to execute certain code.

if (x > 10) {
printf("x is greater than 10\n");
} else {
printf("x is less than or equal to 10\n");
}

2. Loops

Loops execute a block of code repeatedly for a specified number of times.

for (int i = 0; i < 5; i++) {
printf("%d\n", i);
}

Functions in C

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Functions are blocks of code that perform a specific task. They can be called from other parts of the program to reuse code.

Function Declaration

int add(int x, int y) {
return x + y;
}

Function Call

printf("%d\n", add(5, 3));

This is a basic overview of the C programming language. With practice and patience, you’ll become proficient in writing efficient, portable code.

Practice Exercise

Write a program that asks for the user’s name and age, then prints out a personalized greeting.

#include <stdio.h>

int main() {
char name[100];
int age;

printf("Enter your name: ");
fgets(name, 100, stdin);
name[strcspn(name, "\n")] = 0; // Remove the newline character

printf("Enter your age: ");
scanf("%d", &age);

printf("Hello, %s! You are %d years old.\n", name, age);

return 0;
}