what I am trying to do is to pass to a function the address of an array of structs, so I can later modify the items within the struct, within the array
Code:
typedef struct { //A struct of name auctionint bidder;float bid;} auction;
void myFunction (auction * auctionItem[]){(*aucItem[x]).bid = y;(*aucItem[x]).bidder = z;}
int main(){auction theItems[10];
myFunction(theItems);} Where x, y, and z can be any number.
When I try to run my code the IDE (I'm using Code::Blocks 12.11) does not give me any errors, but it does give me a warning:
warning: passing argument 3 of '<function name>' from incompatible pointer type [enabled by default]
and the note:
note: expected 'struct <struct name> **' but argument is of type 'struct <struct name> *'.Also, when I run the program, it will crash and return garbage.
Background: I'm writing a convolutional encoder (and decoder, eventually) for a microprocessor (PIC24), for which I'm using structs and pointers to move from state to state. So far as I'm aware, everything I'm using in the PIC involves nothing other than ANSI C.
I have a little experience with structures, having written a linked-list program for a class a couple years back, but nothing since and never used structure arrays. I have the feeling I'm missing something basic here, which is what's so frustrating. The most confusing error (and I suspect the root of most of them) is the 'state undeclared', which I just can't figure.
The errors I'm getting are:
encoder.c:11: warning: 'struct memstate' declared inside parameter list encoder.c:11: warning: its scope is only this definition or declaration, which is probably not what you want encoder.c: In function 'state_init': encoder.c:22: error: two or more data types in declaration specifiers encoder.c:25: error: 'state' undeclared (first use in this function) encoder.c:25: error: (Each undeclared identifier is reported only once
[Code]....
Code:
Code: //Includes #include <stdlib.h> //------------------------------------------------------------------------------ //Creates state machine and passes back pointer to 00 state void state_init(struct memstate* startpoint) { extern struct memstate { char output0; //output if next input is 0
[code]...
NB: I'm aware that at the moment, this code will do nothing except spin round that do-while loop. Once it's actually compiling I'll drop in some simple button-based test code so it'll check for the correct output.
I think i am getting confused with passing structs and functions all in the same...When I run through the program (it compiles), the functions that add coins do not add, but rather just replace an old value with a new one.
#include <cstdlib> #include <iostream> using namespace std; struct coinbox {
I understand why I think. When I am passing the reference to the array possion it is outputting everything up to the next /0. So my question is how do I stop it?
I dont have much choice as to how the output wants it:
struct mystruct{ int n; }; class mscope{ public: std::vector<mystruct> mv;
[Code] .....
So I have a vector of structs and I want to traverse it, find a struct that matches a constraint and obtain a pointer to that struct. I made a function for this purpose which takes a number and an empty pointer that will store the reference. However, after function returns the pointer becomes null. What could be causing this?
I am having a lot of trouble being able to get data from a file and input it into given structs and arrays of structs and then outputting the file. We are given a file that contains 96 lines and looks like this:
Arzin, Neil 2.3 6.0 5.0 6.7 7.8 5.6 8.9 7.6 Babbage, Charles 2.3 5.6 6.5 7.6 8.7 7.8 5.4 4.5
This file continues for 24 different people and then repeats with different scores (the second line). The first number, in this case is 2.3 for both people is a difficulty rating. The next 6 numbers are scores.
We are given this data in order to set up our structs and arrays and my code:
#include <iostream> #include <fstream> #include <iomanip> #include <string> #include <cmath> using namespace std; int main () { ifstream inFile; inFile.open("C://diveData.txt);
I can't seem to remember everything I should about constructors. I'm looking for a way to create an array of structs, using a constructor. My code should explain.
struct myStruct { private: int structInt1, structInt2;
I have an assignment where I need to use pointers to do a few things and I am a little confused on the syntax of it all. My question is how do you use a pointer to point to an array of structs.
For example
struct info{ char firstName[15]; char lastName[15]; }; main() { info person[4]; cout << "The third letter of the second persons first name is: "; // ????? }
how would I define a pointer to point to the third letter of first name the second person in the "person" array.
I have a structure product_array *pa that contains a pointer *arr to an array of structs and count that adds 1 when a new product is added (set to NULL initially). I have to write a function which adds a new product entry to that array. One product entry has *title, *code, stock and price parameters. The array is dynamically allocated and I’m supposed to:
1. Reallocate space for array. 2. Update product_array. 3. Initialize it.
Also, code should be truncated to 7 characters.Products can be added multiple times, so the initial size is unknown.
Code:
void add_product(struct product_array *pa, const char *title, const char *code, int stock, double price) { for (int i = 0 ;; i++){ pa->arr = realloc(pa->arr, sizeof(struct product_array));
Where course code is the 4 numbers after the name together and the term is the letter and year in the last two pieces of info. I got this to work:
int main() { FILE *p; p = fopen("input.csv", "r+"); if(p == NULL) { puts("The file could not be opened");
[Code] ......
But lets say i dont know how many lines i have in my file and i want to count them and then use that size for my array so i tried this by:
int main() { FILE *p; int lines = 1; char ch; p = fopen("input.csv", "r+"); if(p == NULL) {
[Code] .....
But the second program is not working for unknown reasons. I do not get any errors but its not scanning the info because when i print the info later on it prints out random symbols.
void readFile(struct course *d, char* filename){ FILE* fp; char buffer[100]; int i = 0, array_size = 100; struct course *temp;
[code]....
I will be using this to read data from a file. I start with an array of 100 structures being passed to the readfile function. Once it reads 100 lines (i == array_size), I want to double the array size until I have finished reading the file.
Two questions.
1)My initial thought was that I needed to keep track of the lines read with my variable, i. However, is there a better way?
2)My program is crashing right now at the call to double_array_size function. What is wrong with my code? Never dealt with dynamically allocated array of structures and functions.
I read online that I should change my code in the following manner.
I can paste the "error messages" if you like, but it is a page full of stuff I have never seen. glibc detected, Backtrace, Memory Map, and a bunch of numbers and hexadecimal stuff like addresses.
function fun recieves the address(which is NULL) and then allocates the memory for the Box; Let's say I cannot return the address of new allocated p and I can't also use that pointer p(from main) without passing it into a function.
Q: How can I make it that I could operate in function "fun" as I operate on orginal pointer p(from main), right now I'm just passing the address to my function but I can't change the 'global' pointer p ;(.
I remember in pascal it's like: "function(var pointer:[pointer to sth])" and all is done.
And I want to make adding,deleting, and searching functions.Something like
Code:
void add();//Add name and address to a file, //and add more to the same file if I want to. void del();//Delete or Change some neighbor's name or address //in the same file(Can I?) void search();//Search name and show detail
So I started to code adding function first, but I don't know that I need to use pointer to code each functions relations, and I don't know how to check that my input's already exists yet. But I started some code below...
Code: void add() { int i=0; FILE *fp = fopen("neighborhood.txt", "at"); if ( fp != NULL ) { do{
I am increasing my array in multiples of 5 (or in this case, my constant BLOCK). This is the result of my printout (t1-t40 is correct, the rest of the values should be 1):
t1 1 1 t2 1 1 t3 1 31329 t4 31297 1 t5 1 31249 t6 31217 1 and so on .....
I noticed that in my test, realloc was called 7 times. My array has 7 distorted records. Each time I call realloc, it is distorting one of my records.
I'm trying to read the data from a file i/o and put them into an array of structs. But when I run the program, it gives me a bunch of "garbage" as an output. my code and see
I am trying to wright a program that takes student grade data from a command line file, calculates a final grade, and copies the final grades to an output file. So far I have two functions, one that creates a student structure by allocating memory for it and returning its address, and one that should take that address and fill it with data from a line from the input file. My ultimate goal is to use a linked list to connect all the structs, but for now I just want to get the functions working. When I run what I have so far, I get an error C2440 (using visual 2010) that says "cannot convert from 'cStudent *', to 'cStudent', and points to the line where I call my fill function. How should structure pointers be passed?
I'm trying to pass the pointer of a dynamic array into a template function, but it keeps telling me there is no matching function to call because the parameters I'm passing in are wrong. how to make the function accept the pointer.
//main int main() { srand(unsigned(time(NULL))); int size; int *list; int *listCopy;
Is there such thing as passing a winforms label by reference? For example, can I create a pointer label and pass the address to a function? I've looked online but couldn't find anything. Perhaps that's a sign?
The function should pass the square of the first input parameter and the cube of the second input parameter back to the calling routine. I thought I could use a recursion but its not going to work.
Is it possible to pass a class pointer as memory buffer across the socket? The above code is just an example. My question in general is, whether it's possible to pass any Classes pointer as a memory buffer across sockets.
