parameter-passing

问题 When I pass a string to a function, is a pointer to the string's contents passed, or is the entire string passed to the function on the stack like a struct would be? 回答1: To answer your question, consider the following code: void Main() { string strMain = "main"; DoSomething(strMain); Console.Write(strMain); // What gets printed? } void DoSomething(string strLocal) { strLocal = "local"; } There are three things you need to know in order to predict what will happen here, and to understand why

问题 When I pass a string to a function, is a pointer to the string's contents passed, or is the entire string passed to the function on the stack like a struct would be? 回答1: To answer your question, consider the following code: void Main() { string strMain = "main"; DoSomething(strMain); Console.Write(strMain); // What gets printed? } void DoSomething(string strLocal) { strLocal = "local"; } There are three things you need to know in order to predict what will happen here, and to understand why

问题 Though we declare a function with an integer array, we pass address of the array to the function. In the case of simple integers it gives error if we pass address we get pointer conversion error. But how its possible in case of an array #include<stdio.h> void print_array(int array[][100],int x, int y); main() { int i,j,arr[100][100]; printf("Enter the array"); for(i=0;i<2;i++) { for(j=0;j<2;j++) { scanf("%d",&arr[i][j]); } } print_array(arr,i,j); } void print_array(int array[][100],int x,int

问题 I have added the dependency injections to the project. But when i create an instance by using new keyword, dependency injection doesn't work. public class MyClass { ILoginTokenKeyApi _loginTokenKeyApi; public MyClass(ILoginTokenKeyApi loginTokenKeyApi) { _loginTokenKeyApi = loginTokenKeyApi; } ... } When i try to create an instance of MyClass, it wants a parameter to be constructed naturally. Just like this : MyClass mc = new MyClass(); // ERROR, it wants a parameter (but it is what i want) I

问题 I'm trying to make a function that writes a file but i'm having issues passing a string as a parameter. void writeFile(string filename, string letters, int size) { ofstream outputfile("output.txt"); outputfile << letters; outputfile.close(); } int main() { string letters[] = {"u", "l", "s", "n","m", "z", "a", "p", "b"}; int size = 9; string filename = "Inputfile.txt"; writeFile(inputfilename.c_str(),letters,size); } And having this error. error: could not convert from 'std::string* {aka std:

问题 heloo... I have a problem when I want to use date in my code I have a class that named ReportService and in this class I use jdbc to connect my database and after that I want to get a report from my database in a special date.frist I write this : ("select sum(cost) from mem_income where trunc(date_out) = to_date ('31-jul-2013' , 'dd-mm-yyyy')"); and this work good.but after that I want to pass my date from my main class: PreparedStatement pst = conn.prepareStatement("select sum(cost) from mem

问题 Suppose I have a chain of function calls. def func1( pick, arg1, arg2 ): if pick == 1: do stuff with arg1 and arg2 elif pick == 2: do other stuff with arg1 and arg2 return stuff that got done def func2( pick, arg1, arg2, arg3 ): if pick == 1: do stuff with arg1 and arg2 and arg3 elif pick == 2: do other stuff with arg1 and arg2 and arg3 return stuff that got done def func3( pick, func2, arg3 ): if pick == 1: do stuff with funcs and arg3 elif pick == 2: do other stuff with funcs and arg3

问题 I am trying to pass a parameter from AJAX back to my JSP page. Here is my sample code: JS File: $(document).ready(function() { $.ajax({ type: "GET", url: "URL...", dataType: "xml", success: function(xml) { $(xml).find('Rowsets').each(function(){ var x = $(this).find('Auto_Id').text() // Assign data from Auto_Id into variable x document.form.y.value = x; // Pass the parameter back to the JSP page }); } }); }); .JSP File: <FORM name="form"><input name="y" value="" /></FORM> //value left blank

问题 In the following method definitions, what does the * and ** do for param2 ? def foo(param1, *param2): def bar(param1, **param2): 回答1: The *args and **kwargs is a common idiom to allow arbitrary number of arguments to functions as described in the section more on defining functions in the Python documentation. The *args will give you all function parameters as a tuple: def foo(*args): for a in args: print(a) foo(1) # 1 foo(1,2,3) # 1 # 2 # 3 The **kwargs will give you all keyword arguments

问题 I am using JSF 2.2 on Glassfish 4.1. I am trying to pass in a query parameter to as an action method argument as follows: // Example 1. This does not work. // at url http://localhost:8080/app/order.xhtml?email=test@email.com <p:commandButton value="Place order" action="#{orderManager.placeOrder(param['email'])}" /> (Know that param is an implicit EL object.) In the server log I have configured it to print the method parameter, but I can see that an empty string was passed-in, not "test@email