How the First Version of C++ Worked

Once upon a time, in the early 1980s, Bjarne Stroustrup had a wild idea.

He looked at C, the king of system programming languages, and thought, What if I made it better? But, you know, in a way that wouldn’t scare the entire programming world into a panic.

Thus, C++ was born—not as a completely new language, but as an extension of C.

And how did it work? By converting C++ code into plain old C. That’s right! The first C++ compiler wasn’t really a compiler at all. It was a translator that took C++ code and spit out equivalent C code.

The Genius of Translating C++ to C

At the time, this was an incredibly smart move.

Why? Because C compilers were everywhere, battle-tested, and highly optimized. If you could write a tool that transformed this newfangled C++ into C, you could piggyback off the already established infrastructure. No need to reinvent the wheel!

This approach meant that C++ could be used immediately. No waiting around for someone to make a brand-new compiler. Just write some C++ code, run it through the translator, and compile the resulting C code using any existing C compiler. Boom! Instant adoption.

The Early C++ Compiler: Cfront

The first-ever C++ implementation was called Cfront.

It took your fancy C++ classes, inheritance, and function overloading, and transformed them into raw C code. This was both impressive and, let’s be honest, a little terrifying. Imagine writing a clean, elegant C++ program only to see it translated into a monstrous mess of function pointers and struct-based wizardry.

But it worked! And that was the most important thing.

The Achilles’ Heel of C Compatibility

While this method made adoption quick, it also tied C++ to C in ways that would become… problematic.

Maintaining backward compatibility with C meant carrying around decades of legacy baggage. It also meant that C++ had to deal with all the quirks of C, even when they didn’t make sense in an object-oriented world.

For example, certain things in C, like malloc() and free(), made no sense in a world with constructors and destructors. Yet, because C++ had to play nice with C, these features had to stick around. The same thing happened with function pointers, #define macros, and other legacy constructs that C++ might have been better off leaving behind.

Evolution Beyond C

As C++ grew, it started to break away from C in subtle but meaningful ways.

Features like stronger type safety, RAII (Resource Acquisition Is Initialization), and exceptions all made C++ more than just “C with classes.” But at the same time, it became a complex beast. The very thing that made early adoption easy—its C compatibility—was now making the language harder to evolve cleanly.

Eventually, modern C++ compilers stopped using the “translate to C” approach, opting instead for direct compilation. This allowed for better optimizations and more sophisticated language features.

Conclusion

The first version of C++ was a clever hack—a smart, pragmatic way to get an ambitious new language off the ground without scaring away the existing C crowd.

But over time, its deep roots in C became both a blessing and a curse. While it ensured early success, it also introduced complexities that developers still wrestle with today.

Even so, C++ survived, thrived, and continues to evolve, proving that sometimes, a well-placed hack can change the course of programming history.

Key Ideas

References

• The Design and Evolution of C++ - Bjarne Stroustrup
• History of C++
• Early C++ and Cfront