C++ :: delete Function Necessary When Allocation Fails?
Apr 13, 2014
I have a quick question about dynamic memory. I know that if you are dynamically allocating memory for a single data array and it fails, you can immediately abort the program via a return statement, but is this also true with multiple data arrays? For instance:
int *foo, *bar
foo = new (nothrow) int [5];
bar = new (nothrow) int [5];
if (foo == nullptr || bar == nullptr)
return -1;
else
/*rest of execution */
If the answer to the previous question is no, do you need to do a delete[] on the arrays that succeeded before terminating the application? Say foo is correctly allocated but bar fails, would you have to do something like this?
int *foo, *bar
foo = new (nothrow) int [5];
bar = new (nothrow) int [5];
if (foo == nullptr || bar == nullptr) {
if (foo == nullptr && bar != nullptr)
delete[] bar;
1. Pointers can be used as pass by reference. When I dynamically allocated memory for array[50] in the run function, does that mean I am changing the size of the pArray in main as well? Or does the scope of array[50] ends with the function run? if so, should I do a delete [] Array inside the run function?
2. When I do delete[] pArray in main, what does it delete? memory for array[50]? or array[100]?
#include <iostream> using namespace std; void run(int* Array, int& s) { s = 50; Array = new int[s];
What I have is a main function that takes input characters from the command prompt during the main function call, and coverts it to an integer array a using atoi. (starting at the 2nd character - the 1st is reserved for another call that I plan to reference later, and the 0th is obviously the ./function). A function is then called to find the mode of an array (the range of values in the array is 1-30). Now, when I run the whole thing, I get a segmentation fault (core dumped) for even number of arguments. It's late and I've been staring at it for too long...
Code: #include <stdio.h> #include <stdlib.h> int get_mode(int a[], int count);
I'm getting a "passing...discards qualifiers" error on my if statement and not sure why because I'm not changing anything. I know removing const or making test mutable fixes the issue. I've been taught to always make a function const if it doesn't change anything, in which case, have I finally come across an acceptable time to use mutable?
I have to manage a Clinic. I need to delete a booking (for example, if John said he's coming on March 22nd at 15:30 but then he say he's not going to come, I have to delete that booking so another person can use it).
idSearched: the id of the person that is not going to come. I have a lot of specialties and each one has a list. So I ask for the speciality to delete the node (the node contains John's booking). If I don't find it, I return (-1). searchSpecByID return a pointer to the list where the speciality is. So head will point to the first node of the list. In nodeToDelete I have the node I want to delete.
The program detects OK when is the first in the list and when not, but it doesn't delete the node.
int *buildTrail(int antIndex, int start, double *pheromones) { int *trail = new int[tabu]; bool *visited = new bool[tabu]; trail[0] = start; visited[start] = true;
[Code] ....
If I comment all lines includes visited word , no exception occurs , Otherwise , exception throws.
Simply put , How can i delete visited parameter as long as its role has been finished? . . . delete visited ; return trail;
making my delete function work. My program does compile but my delete function doesn't work. I haven't finished my last two functions because I am focusing on the delete but how to Sell a title and print the value of all sold titles would be nice as well.
I am having an issue when i try to delete a node with 2 children it either doesn't delete anything, or wigs out in various manners deleting the wrong node or replacing a node with a various memory location. As follows, here is the delete function:
void BST::dele(){ bool found = false;//initialize a bool type to "find" the element to be deleted if(root == NULL) return;//well if the tree's empty, nothing to be found right? current = root;//set the current to the root to traverse the tree in search of the element node* parent;//create a parent node for use once the node has been deleted while(current != NULL){//traverse the tree
I have written a delete node function to delete a node in a linked list by the index number. Here is the code:
Code:
void delete_node(struct node **start,int index_no) { int counter=0; struct node *current=*start, *prev=NULL;//Current holds start and prev holds previous node of current while(current->next!=NULL)
[Code]....
note that I know if the head node turns out to be the indexed position, there is no way to delete that node in the current coding. But please after correcting the present node add that part of the code separately.
I had an assignment that I completed and it was just inserting values into a binary tree and then displaying it. I was wondering what the code would be if I wanted to delete a number in the binary tree, or if I wanted to search for a number. Here is my code for my assignment.
I have a function and i want to delete a file when the function is called and starts it's loop i have used this code but unfortunately the file is not deleted ?
Code: void evaluate(void) /*evaluate the population */{ int mem; int i; double x[NVARS+1]; char buffer[101] = {"save.txt"};
This function should delete each element in the list which is the same as this one typed by user. There are no errors, but function doesn't work. It deletes something, but not this element which should.
My program seems to be working fine, except for when I call on my delete function. I don't receive any errors, but when I call the delete function my program outputs nothing and freezes. As in, my print function (which is called before the delete function) doesn't even work. I've tried removing bits of the function to see if I could pinpoint where exactly the issue is, but I've had no luck.
#include <iostream> #include <string> using namespace std; class List{ private: struct node{ string _data;
[Code] ....
And the function that is causing me trouble:
void deleteNode(string data){ node* del = NULL; t = h; n = h; while(n != NULL && n->_data != data){
I`ve wrote a function for my utility to XOR char* buffer by a key, then to reverse it with the same key. Here is the code, it`s simple enough:
Code:
static inline char* XOR_buffer(const char* d, const char* k ) { char *newstr = (char*) malloc(sizeof(char)* strlen(d)); newstr[0]=''; printf("%d is size of string ", strlen(d)); char *begin = newstr; char* ret = begin; int len = strlen(k); }
[code]....
The lengh of the string is reduced by the second XOR call. You can try it out, just define XORDBG to view the error message in the second pass to the buffer.
i created an com client that try to create com server with the command CreateInstance. at win 7 it works fine (both 32 and 64 bit). but with xp it fails. i created the app with win 7 - 64 bit.
When I ran it only the calls from doers array is called 7 times normally, and donters only one time. Why is that? When I call doers from the second loop, it prints the doers functions again....and only one call to donters is made to the first static inline donter functions __dont1()...
I'm trying to write a piece of code that calculates the difference in days between two manually input dates. The part of my code that's causing problems is:
xxx
When running the code and prompted to enter the date, if I input for example 31/12/2014, it'll be rejected and send me back to the beginning of the loop. Any date with 31 days involving months 1, 3, 5, 7, 8, 10 or 12 causes this problem. All other valid dates however work perfectly fine (e.g. 30/4/2014).
Something possibly worth mentioning is that, when I take out all other conditions from the loop, i.e.
xxx
it works fine (31/12/2014 is accepted), but of course I need all of the other conditions in there too.
I'm trying to write a wrapper for rapidXML in order to use it in my projects however I've run into a curious bug that's preventing me from properly saving the XML documents I'm working with. The gist of it is: simply parsing a very simple xml doc and then saving the same document to the same file (without modifying it) creates a mostly correct output except for scrambling a few node closures:
As a foot note: I'm almost certain it's not an issue with the parse() function.
If I parse() the document and then call std::cout<<doc; it prints the document perfectly fine to the console, but for some reason std::ofstream<<doc; causes issues.
The code is supposed to display the total and averages of the data as well, but cuts off due to an error in the code. The code should also:
1)Print checks for all employees, one per page, sorted by lastname. The first check number, 100, is to be read from a company data file (see requirement 4). The border of each check is important and should not be omitted.
2)Convert the net pay to a text string for each check printed.
3)Print a reference code on each check. The reference code is obtained by combining the first letter of the lastname with all the consonants remaining after removing all vowels (a,e,i,o,u).
4)Use the same employee data found in assignment 2. Use the following company data, obtained from a text file,
Output I'm expecting: Program to display totals and averages (worked before I turned everything into an array), now exits with error before totals/averages are displayed. Program also writes up a report.txt file that also writes this information into it, as well as using a quicksort to organize the names alphabetically, and print paychecks (all of the #BORDER, #HEADER1-8, #STUB, etc). In that check a reference code is also generated (teacher gave us code, we just had to modify for our final program as seen here)
Flow of the program: Print headings to label all of the input data we will enter soon under the categories as listed in the heading. Initialize all of our totals (in our array) to value of 0. These will be added in a loop "AddAccumulators" which takes our value for the hours, payrate, and taxes from each employee array structure and adds it to the total array. Program will write this information into the report.txt file with the HEADER line for totals, and should be displaying it in that picture. (Same for averages). After all of the data is calculated, the Reference code, Totals, Averages, and individual employee data is taken and put into printing out a Check Header and Stub.
