initialization

问题 Having this: #include <stdio.h> #include <stdlib.h> struct Test { char c; } foo; int main (void) { struct Test **ar; ar=malloc(16); *(ar+1) = &foo; ar[1]->c = 'c'; //this work (*(*ar+1)).c = 'c'; //this does't work return 0; } //(**(ar+1)).c='c'; --> first case Why the above works only the variant with array entry and not pointer dereference? struct Test { char c; } foo; int main (void) { struct Test **ar; ar=malloc(16); *ar=malloc(0); *(ar+1) = &foo; //(**(ar+1)).c='c'; (*(*ar+1)).c='c'; //

问题 Sometimes it looks reasonable to use __init__ as initialization method for already existing object, i.e.: class A(): def __init__(self, x): self.x = x def set_state_from_file(self, file): x = parse_file(file) self.__init__(x) As alternative to this implementation I see the following: class A(): def __init__(self, x): self.init(x) def init(self, x): self.x = x def set_state_from_file(self, file): x = parse_file(file) self.init(x) It seems to me as over-complication of code. Is there any

问题 TL:DR There seems to be a chicken-and-egg paradox in this View initializer. The Code This happens often enough to me that I must be missing something fundamental about @State . Namely the compiler seems to be saying I can't set pickerIndex until pickerIndex has been set, and I can't exit the initializer without setting pickerIndex . (The LetterSelection variable tracks a letter of the alphabet, but I don't think its details are relevant.) 回答1: Note: it is better to provide code "as code", so

问题 i ran into a segfault running the following program #include <iostream> #include <vector> template <typename Derived> struct CRTPBase { CRTPBase() { func(); } void func() { static_cast<Derived*>(this)->_func(); } }; struct CRTPChild : CRTPBase<CRTPChild>{ using CRTPBase<CRTPChild>::CRTPBase; void _func(){ vec.resize(10); vec[0] = 2; } std::vector<int> vec; }; int main() { CRTPChild obj; std::cout << obj.vec[0] << std::endl; } When i replace vec with a member of type int it doesn't segfault

问题 Let's assume we have a class: public class SomeClass { protected SomeClass () { } } In MainClass located in different package I tried to execute two lines: public static void main(String[] args) { SomeClass sac1 = new SomeClass(); SomeClass sac2 = new SomeClass() {}; } Because of protected constructor, in both cases I was expecting program to fail. To my suprise, anonymous initialization worked fine. Could somebody explain me why second method of initialization is ok? 回答1: Your anonymous

问题 Let's assume we have a class: public class SomeClass { protected SomeClass () { } } In MainClass located in different package I tried to execute two lines: public static void main(String[] args) { SomeClass sac1 = new SomeClass(); SomeClass sac2 = new SomeClass() {}; } Because of protected constructor, in both cases I was expecting program to fail. To my suprise, anonymous initialization worked fine. Could somebody explain me why second method of initialization is ok? 回答1: Your anonymous

问题 What is the best way to accomplish the following in C? #include <stdio.h> struct A { int x; }; struct A createA(int x) { struct A a; a.x = x; return a; } struct A a = createA(42); int main(int argc, char** argv) { printf("%d\n", a.x); return 0; } When I try to compile the above code, the compiler reports the following error: "initializer element is not constant" The bad line is this one: struct A a = createA(42); Can someone explain what is wrong? I'm not very experienced in C. Thanks! 回答1:

问题 What is the best way to accomplish the following in C? #include <stdio.h> struct A { int x; }; struct A createA(int x) { struct A a; a.x = x; return a; } struct A a = createA(42); int main(int argc, char** argv) { printf("%d\n", a.x); return 0; } When I try to compile the above code, the compiler reports the following error: "initializer element is not constant" The bad line is this one: struct A a = createA(42); Can someone explain what is wrong? I'm not very experienced in C. Thanks! 回答1:

问题 Background I am testing various saved models as part of an experiment, but one of the models comes from an algorithm I wrote, not from a sklearn model-fitting. However, my custom model is still a linear model so I want to instantiate a LinearModel instance and set the coef_ and intercept_ attributes to the values from my custom fitting algorithm so I can use it for predictions. What I tried so far: from sklearn.linear_model import LinearRegression my_intercepts = np.ones(2) my_coefficients =

问题 Background I am testing various saved models as part of an experiment, but one of the models comes from an algorithm I wrote, not from a sklearn model-fitting. However, my custom model is still a linear model so I want to instantiate a LinearModel instance and set the coef_ and intercept_ attributes to the values from my custom fitting algorithm so I can use it for predictions. What I tried so far: from sklearn.linear_model import LinearRegression my_intercepts = np.ones(2) my_coefficients =