Java doesn’t support true closures, even though using an anonymous class like you are using here (new TimerTask() { … }) looks like a kind of closure. edit – See the comments below – the following is not a correct explanation, as KeeperOfTheSoul points out. This is why it doesn’t work: The variables lastPrice and … Read more
Why forward-declare is necessary in C++ The compiler wants to ensure you haven’t made spelling mistakes or passed the wrong number of arguments to the function. So, it insists that it first sees a declaration of ‘add’ (or any other types, classes, or functions) before it is used. This really just allows the compiler to … Read more
Static variables (file scope and function static) are initialized to zero: int x; // zero int y = 0; // also zero void foo() { static int x; // also zero } Non-static variables (local variables) are indeterminate. Reading them prior to assigning a value results in undefined behavior. void foo() { int x; printf(“%d”, … Read more
A declaration introduces an identifier and describes its type, be it a type, object, or function. A declaration is what the compiler needs to accept references to that identifier. These are declarations: extern int bar; extern int g(int, int); double f(int, double); // extern can be omitted for function declarations class foo; // no extern … Read more
So you have a matrix (Multi dimensional array) with number of ‘a’ rows and ‘b’ columns and you want to turn this matrix into one dimensional array. int l = 0 for(int i=0; i<a; i++){ for(int j=0; j<b ; j++){ narray[l]=oldarray[i][j]; l++; } } this code is valid in java.. but look at the inner … Read more
Since the pointer returned by malloc() is sufficiently well aligned to be used as a pointer to any type, you could (but probably shouldn’t) use: assert(sizeof(float) <= 10); void *data = malloc(10); char *str = data; strcpy(str, “123.4”); float *vp = data; *vp = strtof(str, NULL); …use *vp… free(data); And now you can use *vp … Read more
Enum values should be from the same type. So your second example almost works. If you are using flags, you should give all the values an name or index, not just one: enum cardValue { Val2 = “2”, Val3 = “3”, Val4 = “4”, ValA = “A” }; Also, variable names, class names, enum values, … Read more