I am working on an assignment identical to another post from a couple years ago, for reference here is the thread:
array of pointers to structures sorting addresses by zip code
They way it is written on that thread is almost identical to the way the teacher implied to have it done (only wrote part of the input block). But I am having an error:
When it gets to the output section it outputs then next name along with the zip code... I tried strncpy and strxfrm but both cause more problems than they did work.
The last part of the project is to have the output put out in order of least zip code to most zip code (00000<99999), so this is causing me a real problem and I do not see what exactly is making this happen.
Here is my code (we dont HAVE to use gets but professor suggested using it for this assignment, next lab is to rewrite this using files and fgets rather than I/O redirection):
I have not started the sorting code because I cannot get past this, but once I have proper zip codes I am sure I can make a sort function no problem.
I am using xcode with some breaks to read variables as various points and do not notice anything wrong until it makes it to the output functions, although this page briefly pops up between input and output functions when the breaks are up:
What I'm trying to do with this code is an address book and I have an array of pointers which are returned by malloc whenever I need to add an extra entry in the address book. What I need to do is search for a specific entry using bsearch. I've got an inqSort() function that sorts the table and runs normally, but my program crashes when I try to use bsearch.
Every time an entry is inserted, I inqsort() the array so it's always sorted, and it works as expected. But when I try to call findEntryUI(); from the main() function, the program crashes after entering the name I want to search.
I'm quite new to C and these days I have been playing around with a linked list. I managed to make a working version using pointers, ad only for the sake of learning I was trying to do the same thing just passing the "Object reference" Here is the method that apparently doesn't work..
Code:
struct Node addNode(struct Node head){ int value; struct Node *n; printf("Please enter the value "); scanf("%d", &value);
[Code]...
when I return the function i have something like: head=addNode(head)
Unfortunately it does not work the way I aspect. I suppose that there is something I have left out..
Code: like n->next=&head // passing the address of the head at the next pointer of the struct head =*n //copy the values of the new node to the old head..
There must be something wrong with this line.. return head; What have I done wrong?
I have a linked list where each node contains a pointer to a string, I'm treating the linked list as a text file and each node/string contains each line in the text file.
I have all of that working, but now I need to create a switchLine function that takes in the two line numbers and I need to switch those lines in the text file. I initially thought of switching the pointers to each the next node in the linked list such that the node order changes, but I then realized how much work that would actually take when you need to consider so many cases. So I instead thought of changing the pointers to strings. If I want to switch the 2nd and 3rd line, then I'd want to have the 2nd node in the list have its char * pointer point to the memory position that the 3rd node's char pointer points to, and vice versa.
I have a vector (structures) in a struct (instances). I make a declaration of this struct called instance. The vector is a 3-layer vector of pointers, like so:
vector < vector < vector<scene::IAnimatedMeshSceneNode*> > > structures; (The type is from Irrlicht 3D). I have 3 nested "for" loops which looks similar to the following:
for (int a = 0; a < instance.structures.size(); a++) { /*note:vector size previously set*/ for (int b = 0; b < instance.structures[a].size(); b++){ for (int c = 0; c < instance.structures[a][b].size(); c++) {
if (1) { //checking value of variable not included in snippet
These are currently referencing the pointers, it seems. The program compiles but crashes at this point. I need them to reference the values of the pointers. Problem is, I don't know where to put the dereference operator (*). Where should it go?
I wrote this simplified version of a program i am writing that parses data in UDP packets. In the process of doing so i pretty much answered all my questions and fix all the problems i was having.
decodeSystemMap function will be in loop, and will proccess packets that have mostly the same data, only a few items will be added or changed or deleted.
whats the best way to check if there are any new, deleted, or removed items in the packet and only modify those? Is there anything unsafe / dangrous about the way the code is now?
Code: /* * File: main.c * Author: david * * Created on May 23, 2013, 11:57 AM */
I'm trying extremely hard to understand pointers and I have the basic concept down.. I feel as though my knowledge of dynamically allocated pointers and pointers in general is not enough to understand the logic behind what I'm trying to do. The problem is that the donations array must be able to accept any number of donations. I've made it do just that, but there is also an array of pointers which must each point to the same element in the donations array. The program works if I assign int *arrPtr[100] for example, but it does not work if I try to dynamically allocate it to accept the same number of elements for donations entered by the user. Here it's the snippet
#include <iostream> using namespace std; //Function Prototypes
I am trying to initialize an array of pointers to an array of characters, I can do it in 3 lines but I really want to do it in one line at the same time keeping the #define.
I am trying to pass a struct through an array to another array from one microprocessor to another microprocessor and then dereference that array to update the same exact struct on the other microprocessor.My goal is to always have values inside of both structs while sending any updates to the struct on the other microprocessor in the mean time but I seem to be looping through the data and the members of the struct seem to be cleared out after every clock cycle. I can verify this by the flashing of my leds which the struct controls.
It doesn't make sense to me why this is working. The way my mind is thinking about this is that vertices is an array of type VertexPos, so then why can it be initialized with objects of type XMFLOAT3?
I have to search an array of struct students on the basis of their first names, last names and roll numbers .. so far i am done with the input of the student first , last names and roll numbers . I have problem in searching the array ..
I basically just want a function that tells me if 'X' or 'O' won in a tic-tac-toe game. I don't care about the visuals, I just want a function that tells me if 'X' or 'O' won. If X wins, return 0. If Y wins, return 1.
How to do the diagonals, but as far as the across and down wins, I know I have to use a nested for loop, but am a little stuck, as to exactly how to set it up.
struct Speaker { static int numElem; string name; int number; // Phone string topic; float fee; };
// IN main() FUNCTION Speaker s[10];
The goal is for numElem to keep track of how many of the 10 elements are in use. However, I'm not sure the proper way to access the element, if it's even possible.
I want to delete selected records from struct array using cstring reading from files. Here I read my records to stud struct then assign non-deleted to stu struct but its not deleting as desired...strcmp is giving 25
while(cont=='Y'){ cout<<"Enter student ID to delete: "; cin.ignore(); cin.getline(id, 15,
[Code] ....
I did some debugging effort and I found here is the problem..the stud[0].ID and id is not same but why? I am giving in same id and both char array lenght is 15
while(cont=='Y'){ cout<<"Enter student ID to delete: "; cin.ignore(); cin.getline(id, 15); cout<<strlen(stud[0].ID)<<" "<<strlen(id)<<endl;///---> lenght 1 is 10 ///---->lenght 2 is 8 cout<<strncmp(id,stud[0].ID, 10 )<<endl;
Okay so I have a question. Lets say I want to create arrays of exact size for abstract data type members. For example:
struct student { char name[10]; int idNumber; };
My question is how to declare this array as null so that later i can give it an exact size to match the length of the name. if it were not a part of the struct i would imagine that the code would look something like this:
I've been working for some number of days on this code to take information about movies from both a file and the user, store the infos in an array of structs, and at the end, write all the info out to a file. I'm having some problems with an error message reading:
"prog.c:102:11: error: subscripted value is neither array nor pointer nor vector"
this error occurs in many lines (which I will label specifically below -- they are everywhere where I am trying to access/modify an individual element of a struct element of the array).
A few examples of where I am having the problems are lines: 39, 52-55, 70, 72, and 86 (and more of the same exact variety).
I am obviously rather systematically doing something wrong, but I am quite certain all of these are the exact same mistakes.
I pull up also 2 or 3 other errors, but I don't think they are related and should be able to fix them quickly once I work out this conundrum.
#include <string.h> #include<stdlib.h> #include <stdio.h> int moviecount =0; typedef struct{ int year;
You should be able to enter those fields, and after some time when while loop is stopped (when u press n) it should print out that PhoneBook bellow. I don't understand what is the problem but I think it is that Display function.
I was attempting something weired with address to move data around when I discovered that the size of the array is not what I expected. I am passing this structure as &Users to a function that declares it as a void *, then I can deal with chunks of data (memmove) and not have to worry about index or things like that. However...sizeof is returning something I do not understand.
I thought that if I were to access Buffer1 via BufPtrs[0], I would simply just put an * to it before printf()-ing or store it in a char[] (equivalent to a string).
How do I store pointers to a struct in an array ? I am using sprintf to concatenate some values together and then output it to an array in its 1st argument. A portion of my code is shown below.
