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AES Encryption for an NSString on the iPhone
... const char * argv[]) {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
NSString *key = @"my password";
NSString *secret = @"text to encrypt";
NSData *plain = [secret dataUsingEncoding:NSUTF8StringEncoding];
NSData *cipher = [plain AES256EncryptWithKey:key];
pr...
Is the practice of returning a C++ reference variable evil?
...
return i; // DON'T DO THIS.
}
That is all sorts of evil. The stack-allocated i will go away and you are referring to nothing. This is also evil:
int& getInt() {
int* i = new int;
return *i; // DON'T DO THIS.
}
Because now the client has to eventually do the strange:
int&...
Anatomy of a “Memory Leak”
...on has a memory problem when monitoring shows that more and more memory is allocated to your process after each garbage collection cycle. In such case, you are either keeping too much in memory, or some underlying unmanaged implementation is leaking.
For most leaks, resources are recovered when the...
Why is there extra padding at the top of my UITableView with style UITableViewStyleGrouped in iOS7
...w.tableHeaderView = nil;, I do:
self.tableView.tableHeaderView = [[UIView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, self.tableView.bounds.size.width, 0.01f)];
I like this solution better than setting a somewhat arbitrary contentInset.top because I use the contentInset.top dynamically as well. ...
error C2664: “std::list::list(const std::allocator &)”: 不能将参数 1...
error C2664: “std::list::list(const std::allocator &)”: 不能将参数 1 从 “std::vector”转换为“const std::allocator &”错误日志：error C2664: std::list<_Ty>::list(const std::allocator<_Ty> &): 不能将参数 1 从std::vector<_Ty>转换为const std::...错误日志：
error ...
Performance of Arrays vs. Lists
...t to and probably less than the capacity of the _items array. The array is allocated with excess capacity to make adding future items quicker by not requiring re-allocation for every addition.
– Trasvi
Dec 17 '15 at 0:42
...
When should I use the new keyword in C++?
...
Method 1 (using new)
Allocates memory for the object on the free store (This is frequently the same thing as the heap)
Requires you to explicitly delete your object later. (If you don't delete it, you could create a memory leak)
Memory stays al...
Why should C++ programmers minimize use of 'new'?
...
There are two widely-used memory allocation techniques: automatic allocation and dynamic allocation. Commonly, there is a corresponding region of memory for each: the stack and the heap.
Stack
The stack always allocates memory in a sequential fashion. It c...
What’s the difference between “Array()” and “[]” while declaring a JavaScript array?
...ray access. There's no control to prove that the browsers are actually pre-allocating the memory (which the specification does not say they must do). If we can assume that array access is constant and the majority of the time will be spent allocating memory in both examples then [] could be prefera...
What are Runtime.getRuntime().totalMemory() and freeMemory()?
...hy there is a totalMemory() AND a maxMemory(). The answer is that the JVM allocates memory lazily. Lets say you start your Java process as such:
java -Xms64m -Xmx1024m Foo
Your process starts with 64mb of memory, and if and when it needs more (up to 1024m), it will allocate memory. totalMemory...