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Why use pointers? [closed]
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Why use pointers over normal variables?
Short answer is: Don't. ;-) Pointers are to be used where you can't use anything else. It is either because the lack of appropriate functionality, missing data types or for pure perfomance. Mo...
What is the difference between & and && in Java?
... true , and the & operator is used to do Bit-wise operations on two integer types.
13 Answers
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Python Pandas: Get index of rows which column matches certain value
...the index,
In [56]: idx = df.index[df['BoolCol']]
In [57]: idx
Out[57]: Int64Index([10, 40, 50], dtype='int64')
then you can select the rows using loc instead of iloc:
In [58]: df.loc[idx]
Out[58]:
BoolCol
10 True
40 True
50 True
[3 rows x 1 columns]
Note that loc can also ac...
Why is it impossible to build a compiler that can determine if a C++ function will change the value
... variable and 0 when the function doesn't. Then what should this program print?
int variable = 0;
void f() {
if (modifies_variable(f, variable)) {
/* do nothing */
} else {
/* modify variable */
variable = 1;
}
}
int main(int argc, char **argv) {
if (modifi...
How to sort with a lambda?
... have written so far makes little sense. If mProperty is supposed to be an int a.mProperty>b.mProperty will definitely yield a bool.
– sellibitze
Feb 26 '11 at 0:32
1
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Using [UIColor colorWithRed:green:blue:alpha:] doesn't work with UITableView seperatorColor?
... division by itself: (from http://github.com/Jon889/JPGeneral)
//.h file
@interface UIColor (JPExtras)
+ (UIColor *)colorWithR:(CGFloat)red G:(CGFloat)green B:(CGFloat)blue A:(CGFloat)alpha;
@end
//.m file
@implementation UIColor (JPExtras)
+ (UIColor *)colorWithR:(CGFloat)red G:(CGFloat)green B:(...
Java Generics (Wildcards)
... E, we can get elements out of the structure, but we cannot put
elements into the structure
List<Integer> ints = new ArrayList<Integer>();
ints.add(1);
ints.add(2);
List<? extends Number> nums = ints;
nums.add(3.14); // compile-time error
assert ints.toString().equals("[1, 2, 3...
Get a list of distinct values in List
...
Not before the Distinct() but after, if you are trying to convert to a list. Ex: Notes.Select(x => x.Author).Distinct().ToList();
– MTwiford
Apr 4 '17 at 20:03
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what is the difference between const_iterator and iterator? [duplicate]
...here is no performance difference.
A const_iterator is an iterator that points to const value (like a const T* pointer); dereferencing it returns a reference to a constant value (const T&) and prevents modification of the referenced value: it enforces const-correctness.
When you have a const r...
What does java.lang.Thread.interrupt() do?
Could you explain what java.lang.Thread.interrupt() does when invoked?
9 Answers
9
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