I think that both are wrong in C++171 and that the expected output should be: 4294967295 0 While the returned value is correct for the latest versions of both compilers, I think that the ios_base::failbit should be set, but I also think there is a confusion about the notion of field to be converted in … Read more
To round a double up to 2 decimal places, you can use: #include <iostream> #include <cmath> int main() { double value = 0.123; value = std::ceil(value * 100.0) / 100.0; std::cout << value << std::endl; // prints 0.13 return 0; } To round up to n decimal places, you can use: double round_up(double value, int … Read more
It skips all whitespace (spaces, tabs, new lines, etc.) by default. You can either change its behavior, or use a slightly different mechanism. To change its behavior, use the manipulator noskipws, as follows: cin >> noskipws >> a[i]; But, since you seem like you want to look at the individual characters, I’d suggest using get, … Read more
[…] so that must mean that the operator returns a bool […] Nope, it returns std::cin (by reference). The reason why while(std::cin >> value); works is because std::istream (which is the type of std::cin) has a conversion operator. A conversion operator basically permits a class to be implicitly (if it is not marked explicit) to … Read more
cout << “Press Enter to Continue”; cin.ignore(); or, better: #include <limits> cout << “Press Enter to Continue”; cin.ignore(std::numeric_limits<streamsize>::max(),’\n’);
When reading from std::cin, it’s preferable not to use the stream extraction operator >> as this can have all sorts of nasty side effects. For example, if you have this code: std::string name; std::cin >> name; And I enter John Doe, then the line to read from cin will just hold the value John, leaving … Read more
You need to include the header file <limits>, which is where std::numeric_limits is defined. Your Mac compiler was helping you out by automatically including that header file; however, you should not rely on that behavior and explicitly include any header files you need.
Let’s take std::cin.getline() apart. First, there’s std::. This is the namespace in which the standard library lives. It has hundreds of types, functions and objects. std::cin is such an object. It’s the standard character input object, defined in <iostream>. It has some methods of its own, but you can also use it with many free … Read more
Yes, you can input multiple items from cin, using exactly the syntax you describe. The result is essentially identical to: cin >> a; cin >> b; cin >> c; This is due to a technique called “operator chaining”. Each call to operator>>(istream&, T) (where T is some arbitrary type) returns a reference to its first … Read more
This line ignores the rest of the current line, up to ‘\n’ or EOF – whichever comes first: ‘\n’ sets the delimiter, i.e. the character after which cin stops ignoring numeric_limits<streamsize>::max() sets the maximum number of characters to ignore. Since this is the upper limit on the size of a stream, you are effectively telling … Read more