Page History

...

Each member of an initialization list should be placed on a separate line. However, if the initialization list consists of one element, it can be kept on the same line. Colons in class definitions should be surrounded with spaces.

structclass A
{
    int foo = 0;

protected:
    int bar = 1;

public:
    A(int const std::int32_t arg_foo) : foo(arg_foo) { }

    A(int const std::int32_t arg_foo, int const std::int32_t arg_bar) :
        foo(arg_foo),
        bar(arg_bar)
    { }

protected:
    std::int32_t bar = 1;

private:
    std::int32_t foo = 0;
};

Note that some older sources use a different convention that is now deprecated, due to the fact that it could not be enforced with autoformatters.

...