You could probably write C++ code in C#, Java and PHP, but it would be hideous. I've seen Fortran written in C, and Pascal written in C++, and C written in Java

You could probably write C++ code in C#, Java and PHP, but it would be hideous. I've seen Fortran written in C, and Pascal written in C++, and C written in Java, and it's generally an unholy mess.