Your code exhibits undefined behaviour because you passed a non-static, uninitialised pointer to realloc whose contents were indeterminate. From C11, Memory Management Functions: The realloc function deallocates the old object pointed to by ptr and returns a pointer to a new object that has the size specified by size. ….if ptr does not match a … Read more
What you’re doing will work. Each time you increment contents, you also increment counter, so contents – counter gives you the original pointer that you can free. Of course, a better way of doing this would be to use a temporary pointer to increment through the allocated memory so you can use the original to … Read more
When you declare the object inside the loop, a new object will be created on each iteration and the exising one destroyed at the end of each iteration. This is because the object will have a scope inside the {}. When you declare it outside, a single object is created and you work with that, … Read more
In the real world, dynamic allocation is slower than automatic allocation. That’s true — at least in general. That doesn’t mean that dynamic allocation is too slow. The only way to determine that is to profile your code. Until you have done that, it is impossible to say that you should abandon dynamic allocation because … Read more
%d actually is used for printing int. Historically the d stood for “decimal”, to contrast with o for octal and x for hexadecimal. For printing double you should use %e, %f or %g. Using the wrong format specifier causes undefined behaviour which means anything may happen, including unexpected results. 5 solved a is a double, … Read more
Simplest answer: Purchase more RAM. If you work in R with large datasets often, it’s worth it. If you don’t have enough memory to load your files, you may not have enough to manipulate them as you want either. Let’s assume that you could hold this data in RAM and manipulate it as you wish … Read more
This is just a manifestation of data locality. It takes less time to look at something at the next page of a book than something at the 800th next page. Try for yourself at home. 2 solved Dereferencing iterators performance
Returning a pointer isn’t a problem as long as it points to memory that is still in scope, such as dynamically allocated memory, global data, or local variables that still exist further up the call stack. The problem with the above code is that you’re dereferencing a pointer without assigning anything to it. This: *ret_val … Read more
What algorithms are used? Java uses TLAB (Thread Local Allocation Buffers) for “normal” sized objects. This means each thread grab some Eden space and turns this grab of memory into individual objects. Thus small objects are typically sequential in memory for that thread, except if a new chunk of memory needs to be grabbed. Large … Read more
What is ‘code’ memory and it is a part of which memory (RAM or Flash memory)? Is one of the sections of a program in an object file or in memory, which contains executable instructions. Code and read-only data are stored in flash memory. When are the local and global variables allocated in memory — … Read more
What’s the difference between the given two codes. One gives time limit exceeded when run on ideone and the other works fine [closed] solved What’s the difference between the given two codes. One gives time limit exceeded when run on ideone and the other works fine [closed]
Can anyone explain to me what just happened here ? Roughly speaking, you converted an address 64 bit virtual address to a virtual page number and an offset, using the right-shift operator (>>) and the bitwise AND operator (&). And what to shall I do to write such a program but in Java as long … Read more
Whenever you have Python code that is: Recalling The Same Function So That If The User Does Not Chose One Of The Other Statements Then They Can Try Again Rather Than The Program To Stop Working, you are almost always better off replacing the recursive call with a loop. In this case the recursion is … Read more
This isn’t possible in general. If you tried it, it might fail in subtle and unpredictable ways. Here are a few potential problems: The process might store its process ID and thread IDs. When you restore it, there is no good way to ensure it gets the same IDs. The process might have files locked. … Read more
Okay I will explain the problem. Computers has limited memory ( modern personal one has about 8 Gigabytes). Operating systems and apps need the memory so their code can be loaded into it and executed by the CPU. Modern systems split the memory into equally sized chunks called pages, the actual page size differs from … Read more