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Advanced 14 min readModule: Module 2: Variables, Types & Memory Footprint

Data Types, sizeof & Type Casting (static_cast)

Inspect byte sizes of fundamental types with sizeof and perform safe type conversions with static_cast.

What You Will Learn in This Lesson

  • Exact bit-width types (int32_t, int64_t, size_t) from <cstdint>
  • Inspecting memory footprint with sizeof
  • Modern C++ explicit type casting with static_cast<T>(val)

Introduction & Core Concept

In C++, every variable has an exact byte size in memory determined by the compiler and CPU architecture.
WHY DOES THIS MATTER IN THE REAL WORLD?

Using C-style casts (int)val bypasses type safety. static_cast checks conversions at compile time.

Memory Sizing & Safe Casting

cpp
cpp
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#include <iostream>
#include <cstdint>
 
int main() {
    int32_t count = 42;
    double ratio = static_cast<double>(count) / 10.0;
    std::cout << "Size of int32: " << sizeof(count) << " bytes" << std::endl;
    std::cout << "Ratio: " << ratio << std::endl;
    return 0;
}

Line-by-Line Technical Breakdown

1Memory alignment rules ensure variables align to CPU cache boundaries.

Try It Yourself (Interactive Editor)

Modify the code in real-time and click Run to test live browser output and console logs.

Intelligent Code Runner & Live Sandbox[CPP]
CPP SOURCE EDITOR
Interactive Live Code

Industry Best Practices & Professional Standards

  • Always prefer static_cast over C-style parenthetical casts.

Lesson Summary & Core Takeaways

  • Precise byte control allows C++ systems to optimize hardware utilization.