When you add the const keyword to a method the this pointer will essentially become a pointer to const object, and you cannot therefore change any member data. (Unless you use mutable, more on that later). The const keyword is part of the functions signature which means that you can implement two similar methods, one … Read more
Tentative definition is allowed in C but not in C++. A tentative definition is any external data declaration that has no storage class specifier and no initializer. C99 6.9.2/2 A declaration of an identifier for an object that has file scope without an initializer, and without a storage-class specifier or with the storage-class specifier static, … Read more
If you really to assign values (as opposed to initialize), you can do it like this: GLfloat coordinates[8]; static const GLfloat coordinates_defaults[8] = {1.0f, 0.0f, 1.0f ….}; … memcpy(coordinates, coordinates_defaults, sizeof(coordinates_defaults)); return coordinates;
In C, the statement int a; when made at file scope, is a declaration and a tentative definition. You can have as many tentative definitions as you want, as long as they all match each other. If a definition (with an initializer) appears before the end of the translation unit, the variable will be initialized … Read more
The short answer is that computing power and resources advanced exponentially between the time that C was defined and the time that Java came along 25 years later. The longer answer… The maximum size of a compilation unit — the block of code that a compiler processes in a single chunk — is going to … Read more
Only x is a pointer to int; y and z are regular ints. This is one aspect of C declaration syntax that trips some people up. C uses the concept of a declarator, which introduces the name of the thing being declared along with additional type information not provided by the type specifier. In the … Read more
The const modifier is trivial: it modifies what precedes it, unless nothing precedes it. So: char const* buffer; // const modifies char char* const buffer; // const modifies * , etc. Generally, It’s best to avoid the forms where nothing precedes the const, but in practice, you’re going to see them, so you have to … Read more
I haven’t done this in a while! Start with foo and go right. float * (*(*foo())[SIZE][SIZE])() foo is a function with no arguments… Can’t go right since there’s a closing parenthesis. Go left: float * (*(* foo())[SIZE][SIZE])() foo is a function with no arguments returning a pointer Can’t go left further, so let’s cross the … Read more
Outside of any function, int x; is a tentative definition, and some compilers and linkers treat them as a sort of “cooperative definition,” where an identifier can be declared this way in multiple files and will result in defining only one object. C’s rules for external declarations (declarations outside of functions) are a bit complicated … Read more
It is allowed to declare a variable in the control part of a nested block, but in the case of if and while, the variable must be initialized to a numeric or boolean value that will be interpreted as the condition. It cannot be included in a more complex expression! In the particular case you … Read more