1. Introduction: From Python to C

1.1 Key Differences Overview

Some of you might ask, What does it mean by Static Typing vs Dynamic Typing ?

Dynamic Typing ( Python ):

• Variables can change their data type during program execution
• Type checking happens at runtime
• No need to declare variable types explicitly
• More flexible but can lead to runtime errors

# Python - Dynamic Typing
x = 5        # x is an integer
x = "Hello"  # Now x is a string (allowed!)
x = 3.14     # Now x is a float (also allowed!)

Static Typing ( C ):

• Variables must be declared with a specific data type
• Type checking happens at compile time
• Once declared, a variable cannot change its type
• Less flexible but catches type errors before program runs

// C - Static Typing
int x = 5;           // x is declared as integer
x = "Hello";         // ERROR! Cannot assign string to integer variable
float y = 3.14f;     // y must be declared as float to store decimal numbers

Advantages of Static Typing ( C ):

• Errors caught during compilation, not during execution
• Better performance (no runtime type checking needed)
• More predictable memory usage
• Clearer code documentation (types are explicit)

Advantages of Dynamic Typing ( Python ):

• Faster prototyping and development
• More flexible for rapid changes
• Less verbose code
• Easier for beginners to learn

1.2 Basic Program Structure

Python:

# Simple Python program
print("Hello, World!")

C:

#include <stdio.h>

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

Key Points:

• C requires explicit inclusion of header files (such as #include <stdio.h>)
• Every C program must have a main() function
• C statements end with semicolons (;)
• C uses curly braces {} to define code blocks
• Functions must explicitly return a value except for void function (we will learn more about this on the next module)