In some cases, yes, it is legal for a derived class to override a virtual function using a different return type as long as the return type is covariant with the original return type. For example, consider the following: class Base { public: virtual ~Base() {} virtual Base* clone() const = 0; }; class Derived: … Read more
I would suggest std::vector<char>: std::vector<char> recvmsg() { std::vector<char> buffer(1024); //.. return buffer; } int main() { std::vector<char> reply = recvmsg(); } And then if you ever need char* in your code, then you can use &reply[0] anytime you want. For example, void f(const char* data, size_t size) {} f(&reply[0], reply.size()); And you’re done. That means, … Read more
Use RETURN QUERY: CREATE OR REPLACE FUNCTION word_frequency(_max_tokens int) RETURNS TABLE (txt text — also visible as OUT param in function body , cnt bigint , ratio bigint) LANGUAGE plpgsql AS $func$ BEGIN RETURN QUERY SELECT t.txt , count(*) AS cnt — column alias only visible in this query , (count(*) * 100) / _max_tokens … Read more
impl Trait is not equivalent to returning an interface or base class object. It’s a way of saying “I don’t want to write the name of the specific type I’m returning”. You’re still returning a value of a single, specific type; you just aren’t saying which type. Each of those branches is returning different types, … Read more
I usually do this using zip: >>> df = pd.DataFrame([[i] for i in range(10)], columns=[‘num’]) >>> df num 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 >>> def powers(x): >>> return x, x**2, x**3, x**4, x**5, x**6 >>> df[‘p1’], df[‘p2’], df[‘p3’], df[‘p4’], df[‘p5’], … Read more
From the documentation class typing.Union Union type; Union[X, Y] means either X or Y. Hence the proper way to represent more than one return data type is from typing import Union def foo(client_id: str) -> Union[list,bool] But do note that typing is not enforced. Python continues to remain a dynamically-typed language. The annotation syntax has … Read more
The return value for main indicates how the program exited. Normal exit is represented by a 0 return value from main. Abnormal exit is signaled by a non-zero return, but there is no standard for how non-zero codes are interpreted. As noted by others, void main() is prohibited by the C++ standard and should not … Read more
Seems to me that you want this: #include <iostream> struct Point { float X; float Y; }; struct Line { Point Point1; Point Point2; float slope; float yInt; float lineLength; float Angle; }; Line getLine() { Line var; std::cout << “enter the first point:”; std::cout << “\nEnterX and Y coordinates separated by spaces:”; std::cin >> … Read more
If C compiler does not know the function signature, it deduces input parameters based on arguments supplied, and deduces return type to be int. Either declare the function before you use it for the first time: float calculate_fare(int stops); or put entire definition at the top of your translation unit. That is, the error: […] … Read more