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In Ruby on Rails, what's the difference between DateTime, Timestamp, Time and Date?
...ave DATE, DATETIME, TIME and TIMESTAMP column data types; just as you have CHAR, VARCHAR, FLOAT and INTEGER.
So, you ask, what's the difference? Well, some of them are self-explanatory. DATE only stores a date, TIME only stores a time of day, while DATETIME stores both.
The difference between DATE...
std::shared_ptr thread safety explained
...pace std;
struct A
{
int a;
A(int a) : a(a) {}
};
int main(int argc, char **argv)
{
shared_ptr<A> a(new A(1));
shared_ptr<A> b(a), c(a), d(a);
cout << "a: " << a->a << "\tb: " << b->a
<< "\tc: " << c->a << "\td: " <&...
Failure [INSTALL_FAILED_ALREADY_EXISTS] when I tried to update my application
...lease variant
Bonus
I set up an alias in my ~/.bash_profile, to make it a 2char command.
alias bi="gradlew && adb install -r exampleApp.apk"
(Short for Build and Install)
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How does virtual inheritance solve the “diamond” (multiple inheritance) ambiguity?
...virtual void eat(){ std::cout<<"EAT=>D";} };
int main(int argc, char ** argv){
A *a = new D();
a->eat();
delete a;
}
... that way the output is gonna be the correct one: "EAT=>D"
Virtual inheritance only solves the duplication of the grandfather!
BUT you still need ...
Can an enum class be converted to the underlying type?
...t16_t /*v*/) {
std::cout << "uint16_t!\n";
}
int main(int argc, char* argv[]) {
SomeEnum e = B;
write(util::underlying_cast(e));
return 0;
}
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...
What is the in a .vimrc file?
...or example, if you find yourself frequently deleting exactly 3 words and 7 characters, you might find it convenient to map a command via nmap <leader>d 3dw7x so that pressing the leader key followed by d will delete 3 words and 7 characters. Because it uses the leader key as a prefix, you can ...
Determining 32 vs 64 bit in C++
...
static_assert(sizeof(void*) * CHAR_BIT == 32) is more expressive and technically correct (although I don't know any architecture where bytes have different amount of bits than 8)
– Xeverous
Mar 4 '19 at 14:27
...
proper hibernate annotation for byte[]
...dar, java.sql.Date,
java.sql.Time, java.sql.Timestamp,
byte[], Byte[], char[], Character[], enums, and any other
type that implements Serializable.
As described in Section 2.8, the use
of the Basic annotation is optional
for persistent fields and properties
of these types. If the Basic...
How do you use the Immediate Window in Visual Studio?
... { return (x + y);}
void main(){
int a, b, c;
a = 5;
b = 7;
c = Sum(a, b);
char temp = getchar();}
add breakpoint
call commands
https://msdn.microsoft.com/en-us/library/f177hahy.aspx
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What is the effect of encoding an image in base64?
...e64 is the better choice.
Size of base64-images
Base64 uses 64 different characters and this is 2^6. So base64 stores 6bit per 8bit character. So the proportion is 6/8 from unconverted data to base64 data. This is no exact calculation, but a rough estimate.
Example:
An 48kb image needs around 64...