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insert vs emplace vs operator[] in c++ map
I'm using maps for the first time and I realized that there are many ways to insert an element. You can use emplace() , operator[] or insert() , plus variants like using value_type or make_pair . While there is a lot of information about all of them and questions about particular cases, I sti...
How to determine equality for two JavaScript objects?
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If the object(s) can be converted to a JSON string, then it makes an equals() function simple.
– scotts
Nov 14 '12 at 18:28
3
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Do the parentheses after the type name make a difference with new?
...e.
Sometimes the memory returned by the new operator will be initialized, and sometimes it won't depending on whether the type you're newing up is a POD (plain old data), or if it's a class that contains POD members and is using a compiler-generated default constructor.
In C++1998 there are 2 typ...
C++ Returning reference to local variable
... get rid of it
}
Typically you would wrap the pointer in some RAII class and/or a factory function so you don't have to delete it yourself.
In either case, you can just return the value itself (although I realize the example you provided was probably contrived):
int func3()
{
return 1;
}
in...
Unsigned keyword in C++
...of these types can be modified using the keywords signed, unsigned, short, and long. When one of these type modifiers is used by itself, a data type of int is assumed
This means that you can assume the author is using ints.
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Plotting time in Python with Matplotlib
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You must first convert your timestamps to Python datetime objects (use datetime.strptime). Then use date2num to convert the dates to matplotlib format.
Plot the dates and values using plot_date:
dates = matplotlib.dates.date2num(list_of_d...
What's the maximum value for an int in PHP?
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integers. Integer size can be
determined using the constant
PHP_INT_SIZE, and maximum value using
the constant PHP_INT_MAX since PHP
4.4.0 and PHP 5.0.5.
64-bit platforms usually have a maximum value of about 9E18, except on Windows prior to PHP 7, where it was always 32 bit.
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How do I call one constructor from another in Java?
...tor from another (within the same class, not from a subclass)? If yes how? And what could be the best way to call another constructor (if there are several ways to do it)?
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How do you pass a function as a parameter in C?
...e parameter f will be a pointer to a function which has a void return type and which takes a single int parameter. The following function (print) is an example of a function which could be passed to func as a parameter because it is the proper type:
void print ( int x ) {
printf("%d\n", x);
}
F...
Is there a performance difference between i++ and ++i in C++?
We have the question is there a performance difference between i++ and ++i in C?
17 Answers
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