c++type-conversioninitializationuniform-initializationnarrowing

Declaring a variable with two types: "int char"

I'm a C++ beginner, and I'm reading Bjarne Stroustrup's Programming: Principles and Practice Using C++.

In the section on 3.9.2 Unsafe conversions, the author mentioned

When the initializer is an integer literal, the compiler can check the actual value and accept values that do not imply narrowing:

int char b1 {1000};     // error: narrowing (assuming 8-bit chars)

I'm puzzled by this declaration. It uses two types (int and char). I have never seen such declaration in Java and Swift before (the two languages I'm relatively familiar with). Is this a typo or a valid C++ syntax?

Solution

  • It's a mistake in the book. That is not a valid C++ declaration, even without the supposed narrowing conversion.

    It isn't mentioned in any of the erratas on Bjarne Stroustrup's page(4th printing and earlier), though, which is odd. It's a clear enough mistake. I imagine since it's commented with //error few people notice the mistake in the declaration itself.