There is no conversion between the object Long and int so you need to make it from long. Adding a L makes the integer -1 into a long (-1L): Long result = -1L; However there is a conversion from int a long so this works: long result = -1; Therefore you can write like this … Read more
I assume you mean something like this: int *iptr = (int*)malloc(/* something */); And in C, you do not have to (and should not) cast the return pointer from malloc. It’s a void * and in C, it is implicitly converted to another pointer type. int *iptr = malloc(/* something */); Is the preferred form. … Read more
reinterpret_cast should be a huge flashing symbol that says THIS LOOKS CRAZY BUT I KNOW WHAT I’M DOING. Don’t use it just out of laziness. reinterpret_cast means “treat these bits as …” Chained static casts are not the same because they may modify their targets according to the inheritence lattice. struct A { int x; … Read more
This is not stored as an integer by PHP, but a float, this is why you end up with 1.0E+25 instead of 10000000000000000000000000. It’s sadly not possible to use that as an integer value in PHP, as PHP cannot save an integer of that size. If this comes from database then it will be a … Read more
The problem with C-Style casts is that they do a lot under the hood. See here for a detailed explanation: http://anteru.net/2007/12/18/200/ You should try to always use the C++-casts, makes life easier in the long run. The main problem with C-style casts in this case is that you could have written (char*)(&v) while with reinterpret_cast, … Read more
Some investigation in assembly code. (OllyDbg) #include <stdio.h> #include <math.h> int main(void) { int x1 = (int) pow(10, 2); int x2 = (int) pow(10, 2); printf(“%d %d”, x1, x2); return 0; } The related assembly section: FLD QWORD PTR DS:[402000] // Loads 2.0 onto stack SUB ESP,8 FSTP QWORD PTR SS:[ESP] FLD QWORD PTR DS:[402008] … Read more
C++11 added a concept called layout-compatible which applies here. Two standard-layout struct (Clause 9) types are layout-compatible if they have the same number of non-static data members and corresponding non-static data members (in declaration order) have layout-compatible types (3.9). where A standard-layout class is a class that: has no non-static data members of type non-standard-layout … Read more
Because subtraction is coercing up to an integer. As I recall, byte is an unsigned type in C#, so subtraction can take you out of the domain of bytes.
Implementing shouldChangeCharactersInRange method as below does not allow the user input non-numeric characters. – (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string { NSCharacterSet *nonNumberSet = [[NSCharacterSet decimalDigitCharacterSet] invertedSet]; return ([string stringByTrimmingCharactersInSet:nonNumberSet].length > 0) || [string isEqualToString:@””]; } This returns YES if the string is numeric, NO otherwise. the [string isEqualToString@””] is to support the backspace key to … Read more
The attempt to write to *dst is UB if the caller passes you a pointer to a const object, or a pointer to a string literal. But if the caller passes you a pointer to data that in fact is mutable, then behavior is defined. Creating a const char* that points to a modifiable char … Read more