function

问题 This question already has answers here : How to access a local variable from a different function using pointers? (10 answers) Closed 4 years ago . What happens when a pointer to a local variable is returned by a function? for example int* foo() { int local; int* ptr = &local; return ptr; } will compiler issue a warning or will it compile and produce unexpected results?? 回答1: Similar kind of question has already been asked : Stack Overflow, local pointer There are somethings in C which are

问题 New to both stackoverflow and C/C++. Im working through implementing a binary tree and have a simple question. Lets say I have the following: struct Node { int data; Node* right_child; Node* left_child; }; void addNode(Node* tree, int new_data){ if(tree == NULL){ Node* new_tree = new Node; new_tree->data = new_data; new_tree->right_child = NULL; new_tree->left_child = NULL; tree = new_tree; } } int main(){ Node* tree = new Node; tree = NULL; addNode(tree, 3); cout << tree->data << endl; /

问题 I'm developing "Matrix" struct and related methods for the purpose of practicing Go. I made a lot of methods but I realized that all these methods can be changed into functions I'm used to C++ and in C++, if I make a function whose parameter is a type of class, the function cannot use the class' private variable(information hiding) However, when I built a similar code using "Go", a function can access a struct's variable. So I don't get what is different between methods and functions in Go.

问题 The problem is basically about to generate a arithmetic expression from a given 'n' numbers , and the expression should be divisible by 101. we can only have +,-,* operators and expression is left associative. I have tried all the available solution on , that are already mentioned on stack overflow, like closing the expressions with else and many more bool calci(int a[],int n,int sum,int pos,char operato[],deque<int>&q,deque<char>&qc) { if(sum%101==0) { //cout<<"sum:"<<sum<<endl; return true;

问题 The problem is basically about to generate a arithmetic expression from a given 'n' numbers , and the expression should be divisible by 101. we can only have +,-,* operators and expression is left associative. I have tried all the available solution on , that are already mentioned on stack overflow, like closing the expressions with else and many more bool calci(int a[],int n,int sum,int pos,char operato[],deque<int>&q,deque<char>&qc) { if(sum%101==0) { //cout<<"sum:"<<sum<<endl; return true;

问题 I want to write a function that returns a table with all the rows between firstDate and lastDate . The rows have datatype timestamp without time zone They also have to be of a specific node id. This is my function: CREATE OR REPLACE FUNCTION get_measurements_by_node_and_date(nodeID INTEGER, firstDate date, lastDate date) RETURNS TABLE (measurement_id INTEGER, node_id INTEGER, carbon_dioxide DOUBLE PRECISION, hydrocarbons DOUBLE PRECISION, temperature DOUBLE PRECISION, humidity DOUBLE

问题 I want to write a function that returns a table with all the rows between firstDate and lastDate . The rows have datatype timestamp without time zone They also have to be of a specific node id. This is my function: CREATE OR REPLACE FUNCTION get_measurements_by_node_and_date(nodeID INTEGER, firstDate date, lastDate date) RETURNS TABLE (measurement_id INTEGER, node_id INTEGER, carbon_dioxide DOUBLE PRECISION, hydrocarbons DOUBLE PRECISION, temperature DOUBLE PRECISION, humidity DOUBLE

问题 I want to create a list of variations of applying a function to every element of a list. Here is a quick example of what I mean. applyVar f [a, b, c] >> [[(f a), b, c], [a, (f b), c], [a, b, (f c)]] Essentially It applies a function to each element of a list individually and stores each possible application in an array. I'm not too sure how to approach a problem like this without using indexes as I have heard they are not very efficient. This is assuming that the function f returns the same

问题 In the example below the Default trait is used just for demonstration purposes. My questions are: What is the difference between the declarations of f() and g() ? Why g() doesn't compile since it's identical to f() ? How can I return a concrete type out of a impl trait generically typed declaration? struct Something { } impl Default for Something { fn default() -> Self { Something{} } } // This compiles. pub fn f() -> impl Default { Something{} } // This doesn't. pub fn g<T: Default>() -> T {

问题 I have an array with all categories stored in it: $allCatArray = array( ['departments/outdoor/123123/'] => stdClass Object ( [i] => 1 [id] => 'departments/outdoor/123123/' [pid] => 'departments/outdoor/' [name] => 'Child Category Name' ) ['departments/outdoor/'] => stdClass Object ( [i] => 1 [id] => 'departments/outdoor/' [pid] => '0' [name] => 'Main Category Name' ) I need detect the highest category in hierarchy when i have id of lower category in hierarchy. So I have this function: