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Virtual/pure virtual explained
...d Virtual() {
cout << "Derived Virtual called.\n";
}
};
int main() {
Base* bBase = new Base();
Base* bDerived = new Derived();
bBase->NonVirtual();
bBase->Virtual();
bDerived->NonVirtual();
bDerived->Virtual();
}
What is the output of this pr...
When is SQLiteOpenHelper onCreate() / onUpgrade() run?
....
SQLiteOpenHelper versions the database files. The version number is the int argument passed to the constructor. In the database file, the version number is stored in PRAGMA user_version.
onCreate() is only run when the database file did not exist and was just created. If onCreate() returns succe...
How can I find WPF controls by name or type?
...e properly found child. Therefore I added a if (foundChild != null) break; into my code to deal with this condition.
/// <summary>
/// Finds a Child of a given item in the visual tree.
/// </summary>
/// <param name="parent">A direct parent of the queried item.</param>
///...
Can two Java methods have same name with different return types? [duplicate]
...rameters. If there are no parameters, then you must have different names.
int doSomething(String s);
String doSomething(int); // this is fine
int doSomething(String s);
String doSomething(String s); // this is not
share
...
Add a column with a default value to an existing table in SQL Server
...
ALTER TABLE {TABLENAME}
ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL}
CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE}
WITH VALUES
Example:
ALTER TABLE SomeTable
ADD SomeCol Bit NULL --Or NOT NULL.
CONSTRAINT D_SomeTable_SomeCol --When Omitted a Default-Constraint Name is autogenerated...
Use of #pragma in C
...bers) in MSVC:
#pragma pack(push, 1)
struct PackedStructure
{
char a;
int b;
short c;
};
#pragma pack(pop)
// sizeof(PackedStructure) == 7
Here's how you'd do the same thing in GCC:
struct PackedStructure __attribute__((__packed__))
{
char a;
int b;
short c;
};
// sizeof(PackedStruct...
What is the real overhead of try/catch in C#?
...
Three points to make here:
Firstly, there is little or NO performance penalty in actually having try-catch blocks in your code. This should not be a consideration when trying to avoid having them in your application. The performanc...
What is the “continue” keyword and how does it work in Java?
...
Let's see an example:
int sum = 0;
for(int i = 1; i <= 100 ; i++){
if(i % 2 == 0)
continue;
sum += i;
}
This would get the sum of only odd numbers from 1 to 100.
...
In Intellij, how do I toggle between camel case and underscore spaced?
...p the plugin menu, then press:
5 - To snake_case (or to camelCase) which converts to history_of_present_illness
6 - To hyphen-case (or to snake_case) which converts to history-of-present-illness
To make this easier, you could set up a shortcut at File | Settings | Keymap.
A quick search of th...
When should you not use virtual destructors?
...is no need to use a virtual destructor when any of the below is true:
No intention to derive classes from it
No instantiation on the heap
No intention to store in a pointer of a superclass
No specific reason to avoid it unless you are really so pressed for memory.
...