Look at possible implementations of the two operators in own code: // Pre-increment T*& operator ++() { // Perform increment operation. return *this; } // Post-increment T operator ++(int) { T copy = *this; ++*this; return copy; } The postfix operator invokes the prefix operator to perform its own operation: by design and in principle … Read more
Bitwise operators come into play when you have to work with byte- or bit-level data. Here I list a handful of examples using bit operations with code samples (in no particular order): 1. They are common and part of many algorithms in cryptography and hash functions (e.g. MD5). 2. They are also often used if … Read more
char ch=”a”; std::cout << ch << ‘\n’; std::cout << +ch << ‘\n’; The first insertion writes the character a to cout. The second insertion writes the numeric value of ch to cout. But that’s a bit obscure; it relies on the compiler applying integral promotions for the + operator.
I can’t give you the rationale, but I can tell why the compiler has that behavior from the stand point of the rules the compiler has to follow (which might not really be what you’re interesting in knowing). From an old copy of the C# spec (I should probably download a newer version), emphasis added: … Read more
in the expression “Cat” && “Dog” // => “Dog” Because you’re using &&, JavaScript is promising you that it will verify that both sides of the expression are true. In this case, “Dog” is the just the last evaluated thing. To be more explicit, you could do something like var c = “Cat” != null … Read more
In a declaration, it means it’s a pointer to a pointer: int **x; // declare x as a pointer to a pointer to an int When using it, it deferences it twice: int x = 1; int *y = &x; // declare y as a pointer to x int **z = &y; // declare z … Read more
Definition The left-shift operator (<<) shifts its first operand left by the number of bits specified by its second operand. The type of the second operand must be an int. << Operator (MSDN C# Reference) For binary numbers it is a bitwise operation that shifts all of the bits of its operand; every bit in … Read more
The @ is the error suppression operator in PHP. PHP supports one error control operator: the at sign (@). When prepended to an expression in PHP, any error messages that might be generated by that expression will be ignored. See: Error Control Operators Bad uses of the @ operator Update: In your example, it is … Read more
1.-> for accessing object member variables and methods via pointer to object Foo *foo = new Foo(); foo->member_var = 10; foo->member_func(); 2.. for accessing object member variables and methods via object instance Foo foo; foo.member_var = 10; foo.member_func(); 3.:: for accessing static variables and methods of a class/struct or namespace. It can also be used … Read more
if ( (i == j) == k ) i == j -> true -> 1 1 != 123 To avoid that: if ( i == j && j == k ) { Don’t do this: if ( (i==j) == (j==k)) You’ll get for i = 1, j = 2, k = 1 : if ( … Read more