Posted May 18, 2023
For as long as I can remember, I have heard people say C/C++ when referring to a project written in C and or C++. A lot of programming/developer jobs also refer to C/C++ when they need a programmer who knows either C or C++. To most people who have never touched C or C++ this might not seem like a big deal. However, the problem is that when people say this term (C/C++) they make it seem like C and C++ are similar or closely related programming languages. That is not true. Although C++ was based off of C when it was first created, these two languages have slowly drifted apart over the years to the point where they share less and less in common1.
There is probably someone who is going to say, “Well you can write C code in a C++ program, so technically C is a subset of C++.” The only problem is that you can write C code in Zig, Go, Nim, and basically almost every other language out there has a C FFI! So should I refer to Zig, Go, and Nim as C/Zig, C/Go, and C/Nim? Obviously no.
“But C++ is just C with classes!”
No, it isn’t. Anyone who says this obviously has never worked with C++. C++ has completely different standard libraries, implementations, and standards than C. It is true that when C++ was first made it was just C with classes2, that has long been false ever since C++ has implemented features separate from C.
One such case where C++ is incompatible with C is with void pointers. For example, this program will compile with a C compiler (like GCC), but it will not compile with a C++ compiler (like G++):
#include <stdlib.h>
int main() {
int *a = malloc(5);
return 0;
}
All this code does is allocate 5 bytes to an integer pointer a. This program
works perfectly fine when compiled with GCC, but if I compile this program with
G++ this error is returned:
main.c: In function 'int main()':
main.c:4:24: error: invalid conversion from 'void*' to 'int*' [-fpermissive]
4 | int *a = malloc(5);
| ~~~~~~^~~
| |
| void*
The reason this happens is that malloc returns a void pointer and C++ cannot
convert a void pointer into an integer pointer unless it is specifically cast
to an integer pointer.
Another big incompatibility with C and C++ is that C++ is actually incompatible with K&R syntax. Given this example function formatted in K&R syntax:
int gcd(a, b)
int a;
int b;
{
if (b == 0)
return a;
return gcd(b, (a % b));
}
It will compile perfectly fine for GCC (as expected), however G++ gives us another set of errors…
gcd.c:3:9: error: 'a' was not declared in this scope
3 | int gcd(a, b)
| ^
gcd.c:3:12: error: 'b' was not declared in this scope
3 | int gcd(a, b)
| ^
gcd.c:3:13: error: expression list treated as compound expression in initializer [-fpermissive]
3 | int gcd(a, b)
| ^
gcd.c:6:1: error: expected unqualified-id before '{' token
6 | {
| ^
This makes it almost impossible to use K&R syntax with C++ unless you format your function arguments according to ANSI C. (I know not many people care about K&R syntax, but I think that it is still an important difference).
There are also many other things in C that will not transfer over to C++ like complex numbers, default return types, and more, but I think you already get the picture by now. These incompatibilities are not anything that would break the entire C language if used in conjunction with C++, but these small differences slowly add up.
Not differentiating between C and C++ also has the side effect of ostracizing new users. Many beginner programmers are lead by the term “C/C++” to think that they’re basically the same language. In fact there are many tutorials out there that are advertised as “C/C++ tutorials”, continuing the confusion. This can also scare away C beginners by making them think that understanding the complexities of C++ are required to understand C (SPOILER: They’re not). I have fallen for this trap in the past, as well as many others. C is honestly a very simple programming language, C++ is not.
With the new C++ standards given throughout the years like C++11, C++20, and etc. C++ programmers have been given more tools and functions that don’t exist in standard C. This usually results in modern C programs having more lines of code than modern C++, however this means that modern C is usually more readable than modern C++. Here is an example question from LeetCode. Solutions differ, but most C solutions look something like this:
int maximumCount(int *nums, int numsSize) {
int pos = 0, neg = 0;
for (int i = 0; i < numsSize; i++) {
if (nums[i] > 0) pos++;
else if (nums[i] < 0) neg ++;
}
return pos > neg ? pos : neg;
}
Even though this code is pretty compact for C standards it is still very readable. Now for the C++ solutions, there are a lot of variations to this solution so I will use one that’s different enough from C.
int maximumCount(std::vector<int> nums) {
auto [a, b] = std::equal_range(nums.begin(), nums.end(), 0);
return std::max(std::distance(nums.begin(), a), std::distance(b, nums.end()));
}
This uses vector and algorithm from the C++ standard library3.
As you can see this code is much more compact but is definitely not as
readable as the C code. Although the C solution can be compiled by a C++
compiler I wanted to highlight just how different they can be from each other.
This is but one example of how C and C++ programmers have slowly separated
when it comes to programming.
I’m pretty sure everyone knows the C programmer stereotype by now, the only thing is that it is TRUE. Lots of Suckless users and developers only use C and POSIX shell in their programs. Cat-v endorses C and C-like languages, but despises C++. Even Linus Torvalds, the creator Linux and Git, won’t touch C++. Heck, even I love C but I can’t stand programming in C++.
This is probably the biggest reason why employers SHOULD NOT put C/C++ on job descriptions, especially if they’re only looking for C developers. All they are doing is scaring away competent C developers.
If you’re referring to a C program or programmer just say “C”. If you’re referring to a C++ program or programmer just say “C++”. If you’re referring to both used separately say something like:
NOT C/C++
Only if you’re using C together with C++ would it be acceptable to say C/C++.
Please note that although these are real concerns with C and C++, this is more of a rant than anything else (and somewhat satire). ↩︎
Fun fact: C++ was actually called “C with Classes” before it was initially released. ↩︎
Credit to code_report for these two solutions. ↩︎