This is a gcc extension called case ranges, this is how it is explained in the document: You can specify a range of consecutive values in a single case label, like this: case low … high: You can find a complete list of gcc extensions here. It seems like clang also supports this to try … Read more
It assigns user input value to a and prints it out. it is done by using a Statement Expression. Statement Expressions are a gnu gcc compiler extension and are not supported by the C/C++ standards. Hence, any code which uses statement expression is not standard conforming and non-portable. The IBM XL C/C++ v7.0 also support … Read more
The current C++ standard does not require that compilers support VLAs. However, compiler vendors are permitted to support VLAs as an extension. GCC >= 4.7, for example, does. It was originally proposed that VLAs would appear in C++14, however the proposal did not succeed. They also, ultimately, did not appear in C++17.
No, this is not possible portably, and I’m not sure to guess exactly what you want to achieve. Terminology Perhaps you want some non-local jump. Read carefully about setjmp.h, coroutines, call stack, exception handling, continuations, and continuation-passing-style. Understanding what call/cc is in Scheme should be very beneficial. setjmp and longjmp setjmp and longjmp are standard … Read more