Yes Vectors are implemented using template memory allocators that take care of the memory management for you, so they are somewhat special. But as a general rule of thumb, you don’t have to call delete on variables that aren’t declared with the new keyword because of the difference between stack and heap allocation. If stuff … Read more
The behaviour is not specific to the repetition operator (*). For example, if you concatenate two lists using +, the behaviour is the same: In [1]: a = [[1]] In [2]: b = a + a In [3]: b Out[3]: [[1], [1]] In [4]: b[0][0] = 10 In [5]: b Out[5]: [[10], [10]] This has … Read more
First a little reminder (or something new if you didn’t know this before): For any array or pointer p and index i the expression p[i] is exactly the same as *(p + i). Now to hopefully help you understand what’s going on… The array a in your program is stored somewhere in memory, exactly where … Read more
You can’t pass a non-static member function pointer as an ordinary function pointer. They’re not the same thing, and probably not even the same size. You can however (usually) pass a pointer to a static member function through C. Usually when registering a callback in a C API, you also get to pass a “user … Read more
You are changing the pointer, which is not const (the thing it’s pointing to is const). If you want the pointer itself to be const, the declaration would look like: char * const str = “something”; or char const * const str = “something”; // a const pointer to const char const char * const … Read more
The best bet if you must use raw pointers is to make sure that it is either a valid pointer or NULL. Then you can check if it is valid by checking if it is equal to NULL. But to answer your question, you can catch these kinds of things with structured exception handling (SEH). … Read more
The three exceptions where an array does not decay into a pointer are the following: Exception 1. — When the array is the operand of sizeof. int main() { int a[10]; printf(“%zu”, sizeof(a)); /* prints 10 * sizeof(int) */ int* p = a; printf(“%zu”, sizeof(p)); /* prints sizeof(int*) */ } Exception 2. — When the … Read more
In the most normal situation, you can pretty much think of struct A { int i; int foo() { return i; } }; A a; a.foo(); as struct A { int i; }; int A_foo( A* this ) { return this->i; }; A a; A_foo(&a); (Starting to look like C, right?) So you would think … Read more
The first thing you need to understand is that when you pass something to a function, that something is copied to the function’s arguments. Suppose you have the following: void swap1(int a, int b) { int temp = a; a = b; b = temp; assert(a == 17); assert(b == 42); // they’re swapped! } … Read more
The pointer returned by localtime (and some other functions) are actually pointers to statically allocated memory. So you do not need to free it, and you should not free it. http://www.cplusplus.com/reference/clibrary/ctime/localtime/ This structure is statically allocated and shared by the functions gmtime and localtime. Each time either one of these functions is called the content … Read more