Before you start yelling undefined behaviour, this is explicitly listed in N4659 (C++17) i = i++ + 1; // the value of i is incremented Yet in N3337 (C++11) i = i++ + 1; // the behavior is undefined What changed? From what I can gather, from [N4659 basic.exec] Except where noted, evaluations of operands … Read more
Through a little typo, I accidentally found this construct: int main(void) { char foo = ‘c’; switch(foo) { printf(“Cant Touch This\n”); // This line is Unreachable case ‘a’: printf(“A\n”); break; case ‘b’: printf(“B\n”); break; case ‘c’: printf(“C\n”); break; case ‘d’: printf(“D\n”); break; } return 0; } It seems that the printf at the top of … Read more
I’m learning/experimenting with Rust, and in all the elegance that I find in this language, there is one peculiarity that baffles me and seems totally out of place. Rust automatically dereferences pointers when making method calls. I made some tests to determine the exact behaviour: struct X { val: i32 } impl std::ops::Deref for X … Read more
I was reading about order of evaluation violations, and they give an example that puzzles me. 1) If a side effect on a scalar object is un-sequenced relative to another side effect on the same scalar object, the behavior is undefined. // snip f(i = -1, i = -1); // undefined behavior In this context, … Read more
One of my kids is taking Java in high school and had this on one of his tests: Which of the following is a valid identifier in Java? a. 123java b. main c. java1234 d. {abce e. )whoot He answered b and got it wrong. I looked at the question and argued that main is … Read more
Is it possible for C++ code to conform to both the C++03 standard and the C++11 standard, but do different things depending on under which standard it is being compiled? 7 Answers 7
This question already has an answer here: Resolving ambiguous overload on function pointer and std::function for a lambda using + (unary plus) (1 answer) Closed 8 years ago. In Stack Overflow question Redefining lambdas not allowed in C++11, why?, a small program was given that does not compile: int main() { auto test = []{}; … Read more
Maybe I am not from this planet, but it would seem to me that the following should be a syntax error: int a[] = {1,2,}; //extra comma in the end But it’s not. I was surprised when this code compiled on Visual Studio, but I have learnt not to trust MSVC compiler as far as … Read more
How many pointers (*) are allowed in a single variable? Let’s consider the following example. int a = 10; int *p = &a; Similarly we can have int **q = &p; int ***r = &q; and so on. For example, int ****************zz; 14 Answers 14 The C standard specifies the lower limit: 5.2.4.1 Translation limits … Read more
Consider the main axis and cross axis of a flex container: Source: W3C To align flex items along the main axis there is one property: justify-content To align flex items along the cross axis there are three properties: align-content align-items align-self In the image above, the main axis is horizontal and the cross axis is … Read more