C :: Array Containing Pointers To Structures?

Aug 9, 2013

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.

Code:

int count = 0;
struct addx {
int a;

[Code].....

View 1 Replies


ADVERTISEMENT

C :: Array Of Structures And Passing Pointers To Structs

Feb 24, 2013

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.

View 9 Replies View Related

C/C++ :: Regarding Pointers To Structures And Referencing?

Mar 24, 2015

concepts on pointers to structures and referencing for the following two lines.

//address of the variable "struct UIP_IP_BUF" is assigned as srcipaddr
uip_ds6_nbr_add(&UIP_IP_BUF->srcipaddr,
//data type "uip_lladdr_t" pointer points to the address of array an "nd6_opt_llao" with size UIP_ND6_OPT_DATA_OFFSET
(uip_lladdr_t *)&nd6_opt_llao[UIP_ND6_OPT_DATA_OFFSET]

View 5 Replies View Related

C++ :: Pointers Structures And Strings - What To Do With Spaces

Feb 13, 2013

This is my program and i dont know what is the better strategy to display the output perfectly align with the title, when i input a long variable or short the variable move and it does not align with its title. what can i do.

#include <iostream>
#include <string>
#include <string.h>
#include <cstdlib>
#include <cstring>
#include <iomanip>
using namespace std;
struct book {

[Code] ....

View 1 Replies View Related

C++ :: Project Combining Arrays / Pointers And Structures

May 6, 2014

Write a program that uses a record structure to store a Student Name, Student ID, Test Scores, Average Test Score, and Grade. The program should keep a list of test scores for a group of 6 students. The program should ask for the name, ID, and four test scores for each student. Then the average test score should be calculated and stored. The course grade should be based on the following scale:

Average Test Score Course Grade
------------------ ------------
90 - 100 A
80 - 89 B
70 - 79 C
60 - 69 D
59 or below F

A table should be displayed on the screen listing each student's name, ID, average test score, and course grade. Implement with functions.

My code runs but it isnt returning anything (readable/correct) and i have no clue why. This is what i have so far:

#include <iostream>
using namespace std;
const int columns = 4;
struct StuRec //user defined datatype {
int id[6];
char names[6][20];

[Code] .....

it compiles completely but at the end instead of showing the student name ID average score and class grade it shows.... [URL] .....

View 2 Replies View Related

C/C++ :: Project Combining Arrays / Pointers And Structures

May 5, 2014

Write a program that uses a record structure to store a Student Name, Student ID, Test Scores, Average Test Score, and Grade. The program should keep a list of test scores for a group of 6 students. The program should ask for the name, ID, and four test scores for each student. Then the average test score should be calculated and stored. The course grade should be based on the following scale:

Average Test Score Course Grade
------------------ ------------
90 - 100 A
80 - 89 B
70 - 79 C
60 - 69 D
59 or below F

A table should be displayed on the screen listing each student's name, ID, average test score, and course grade. Implement with functions.

My code runs but it isnt returning anything(readable/correct) and i have no clue why. This is what i have so far:

#include <iostream>
using namespace std;
const int columns = 4;
struct StuRec //user defined datatype {
int id[6];
char names[6][20];
int scores[6][4];
double avg[6];
char grade[6];
}; //semi-colon required

[Code] ...

View 8 Replies View Related

C++ :: Passing Data Structures To Function Pointers And Get Values

Sep 26, 2014

typedef struct example_dt_struct {
int a;
float b;
char* c;
};
typedef void(*func)(example_dt_struct *s, int e, int f);
void f(func *n){}

how can i use example_dt_structure with my function pointer into f()

View 5 Replies View Related

C :: Create Array Of Pointers To Pointers Which Will Point To Array Of Pointers

Feb 28, 2014

I'm trying to create an array of pointers to pointers which will point to array of pointers (to strings) I tried

Code:

int i;
char *string[]={
"my name is dave",
"we like to dance together",
"sunny day",
"hello",

[code]...

the app keeps crashing , I don't know how to make the array-elements to point to another array-elements..

View 4 Replies View Related

C :: Storing Array Of Structures

May 4, 2013

So i have a program with the structure

Code:

char record[20];
typedef struct{
int id;
char title[20];
char subject[20];
char faculty [20];
int level;
char fname[25];
}report;
int recno,i;
report list[100];

I need to store the hundred records into a file. What are the functions and elements i should use/introduce.

View 2 Replies View Related

C/C++ :: Initializing Array Of Structures

Feb 25, 2014

How to initialize this array of structures in my code

struct CustomerAddress; {
string street;
string city;
string state;
int zip;

[Code] ....

I am going to be using a boolean variable to mark whether or not a specific field has had data entered into it. I figure the best way to do that is to initialize all the elements of the structures to 0. However, with strings and with the nested structure, I'm not sure how to do this.

View 6 Replies View Related

C :: Reading File To Array Of Structures

Jun 9, 2013

I have to write a program that reads from a text file, which contains a list of stock hourly prices and the company names. Something like this:

78.52 82.56 75.10 71.97 Water Company
22.40 25.68 21.37 22.96 Mega Shipping Inc

There's suppose to one array of companies, where each company will be kept in a structure that contains: a pointer for the name, an array of the prices, and the average price for the day. The structures will be kept in an array of structures.

My question is, how do I read the data from the file and put the data from each line into the next structure in the array of structures? I read the numbers in fine. I just use:

Code: fscanf(fp, "%f", &companyAry[i].hourlyPrices[j]);

But my program crashes when I try to read the name.

Code: fscanf(fp, "%[^]", &companyAry[i].companyName);

I'm thinking it has something to do with the fact the companyName is a pointer.

My structure looks like this:

Code:

typedef struct {
char *companyName;
float hourlyPrices[NUM_PRICES];
float avgPrice;
}
COMPANY;

View 8 Replies View Related

C :: How To Find Duplicates In Array Of Structures

Jul 21, 2014

I have an array of structures with structure def that looks like.

Code:
struct {
char * name;
char * school;
int age;
}

there are multiple people with same name but different ages so i want to list them like.

Name.
age 1
age 2 and so on

The array is sorted by name already.

View 3 Replies View Related

C++ :: Read In Name Of A Vendor Into Array Of Structures

Feb 26, 2013

so im trying to read in the name of a vendor into an array of structures. and write the name into a file.

#include <iostream>
#include <cstring>
#include <cctype>
#include <fstream>
using namespace std;
struct booth

[code]....

View 5 Replies View Related

C++ :: How To Delete Elements In Array Of Structures

Apr 4, 2013

Any example to delete an element in an array of structure?Is it same as deleting an element in an array.ie like this....???

// to delete an element in an array
#include<iostream.h>
#include<conio.h> // for clrscr() and getch()
void main() {
clrscr();
int a[50],n,t,index,i;

[Code] .....

View 1 Replies View Related

C/C++ :: How To Add Info To Array Of Nested Structures

Dec 4, 2014

I am making a basic music library that stores information rather than files. I need to read from a .txt file the artist's name, the album name, the song name, and the song length. What I am confused about is storing the information in an array of Artist structures.

struct Song{
string songName;
int songLength;
};
struct Album{

[Code] ...

How to read the information into an array of Artists. Also, how would I be able to figure out if the artist already exists in the array when adding a song and if the artist does, add the album under the existing artist.This is how I am reading in the info:

Artist newArtist;
Album newAlbum;
Song newSong;
ifstream inF("library.txt");
while(!inF.eof()) {

[Code] ....

View 1 Replies View Related

C/C++ :: Using (delete) Operator On Array Of Structures?

Feb 27, 2013

Suppose I have the following structure

struct b
{
char fullname[100];
char title[100];
bopname
};

and i declare a pointer to the struct as follows

b* bp;

and at runtime,

bp = new b[5];

In the end, is the statement delete[ ] bp enough to release the dynamically allocated memory. Or do i need to separately delete bp[0],bp[1]...

Does delete[ ] bp indicate that the array[ ] pointed by bp has to be deleted?? [I am confused as to how this happens, since the pointer only points at the 1st struct address]

View 2 Replies View Related

C/C++ :: How To Initialize Array Of Structures At Runtime

Aug 26, 2014

I somewhere read "You cannot initialize a structure like that at run time."

Example:
struct item_info {
      char itemname[15];
      int quantity;
      float retail;
      float wholesale;

[Code] ....

But if you want to assign values at run time then you have to do it manually like:

strcpy(item[0].itemname, "rice");
item[0].quantity = 10;
item[0].retail = 40;
item[0].wholesale = 30;

I tried in internet but am unable to know the differences. I want to know the difference between those two in terms of run time and compile time. Explanation required also for below one. Is this run time or compile time? How does we actually decide which is run time and which is compile time!

struct item_info {
      char itemname[15];
      int quantity;
      float retail;
      float wholesale;
      //int quatityonorder;

[Code] ....

View 3 Replies View Related

C :: Reading Data File Into Array Of Structures?

Nov 2, 2014

I'm reading the following file:

Osgood,Marcus 298542123 CHM FR mosgood@whatever.edu
Cronk,Melissa 873489021 BIO SR mcronk@whatever.edu
Pry,Seth 349908431 MTH SO spry@whatever.edu
Langlais,Susan 783323545 ME SR slanglais@whatever.edu
Davis,Nicole 987543345 PHY FR ndavis@whatever.edu

It's supposed to split it up into name, ID number, major, year, and email. The file reads it without any errors, and assigns name to the first part of the structure. However, ID gets assigned the ID, major, year, and email. Then Major gets assigned major, year, and email. Year gets assigned year and email, while email just gets assigned email. I don't know if it has something to do with the loop. For example, this is what I get what I print just the name and the ID.

Cronk,Melissa 873489021BIOSRmcronk@whatever.edu

Pry,Seth 349908431MTHSOspry@whatever.edu

Langlais,Susan 783323545ME

Davis,Nicole 987543345 PHYFRndavis@whatever.edu

Anyway. This is my function code for reading the array. I have it printing the ID number just to see if I can catch the errors earlier:

Code:
#include <stdio.h>
#include <string.h>
#include "functions.h"
void read_data(char filename[], studentinfo_t s[], int *size) {
FILE *infilep;
int countstudents = 0;
infilep = fopen("student_data", "r");

[Code].....

the name is reading correctly, but not anything else!

View 1 Replies View Related

C :: Allocating And Freeing Memory For Array Of Structures

Jul 27, 2014

I have to allocate memory for an array of structures, and my structure looks as following:

Code:
typedef struct {
char *name;
Uint *start_pos;
Uint len;
}
example_struct;

And now I want to allocate memory, for a variable number (so an array) of example_struct, so I first do:
Code:

example struct *all_struct;
int total_num = 3;
//will be set somehow, but for the example I set it on 3 all_struct = malloc (sizeof(example_struct) * total_num);

And now, as far as I now, I will have to allocate for each field of the structure memory, in order to be able to use it later. But I have problem at this point, a problem of understanding:

- I just allocated memory for 3 structures, but don't I have to allocate then memory for each structure separately, or can I just now allocate the fields like this:

Code: all_struct[0].name = malloc.....

But if yes, why the hell this works...

View 10 Replies View Related

C :: Significance Of Int Casting In Program With Array Of Structures

Jun 18, 2013

I am doing an exercise which has to do with International country codes.The user must give a code and the programm will display the corresponding country.

Code:
#include <stdio.h>
#define COUNTRY_COUNT
((int) (sizeof(country_codes) / sizeof(country_codes[0])))
[code]....

View 14 Replies View Related

C++ :: Putting Text File Into Array Of Structures

Feb 14, 2015

I am at a loss with an assignment. I am supposed to read from a text file, with an input of something like this: alphaproleone,stroke,42 1 and Store it into an array of structures and then output it with each word/number starting on a new line. My current code prints out only the first part, and the "a" in alphaproleone is the actual number "21".

#include <iostream>
#include <string>
#include<fstream>
#include<iomanip>
using namespace std;
typedef struct drugtype {
string name, target;
int effectiveness, toxicity;

[Code]...

View 1 Replies View Related

C++ :: Array Of Structures - Storing Product Information

Nov 5, 2013

I have been dealing with this problem for quite some time, I've been assigned to develop a program that can store products' information within structures (the number of products is undefined). I thought I should use an array of structures, but I don't know how to declare it properly. This is what I thought would work:

struct product {
string name;
string in_stock;
float sale_cost;
int id; }
prod [n]; //n being the undefined number of products the user will register/delete/modify

I already saw an example of array of structures, but it uses a defined number.

View 13 Replies View Related

C++ :: Structures - How To Update Space Ship Position In Array

Apr 7, 2013

I want to do this but do not know exactly how to do it:

Create an array of space ship objects and write a program that continually updates their positions until they all go off the screen. Assume that the size of the screen is 1024 pixels by 768 pixels.

I have begun to write a bit code but the problem is when you want to see the space ship moving step for step on the screen I do not know how to create the ship visible so you can see it is moving. Here's my code so far

Code:
#include <iostream>
using namespace std;
struct SpaceShips
{
int x_coordinate;
int y_coordinate;

[Code ......

View 4 Replies View Related

C :: Structures With Consecutive Strings (array Of Characters) As Members

Sep 24, 2014

Code:
#include<stdio.h>
#include<string.h>

typedef struct test
{
char a[5];
char b[10];
}t;

[Code] ....

In Unix (HP-UX) and Linux, the output of above program will be:

t.a=Helloworld!

Instead of the value of t.a ,i.e, "Hello" only.

Why such output? And what is the trick here to print the only value of t.a.

View 1 Replies View Related

C++ :: Structure Record Type In Array - Unresolved Structures

Feb 25, 2015

Why I do have this error message?

1>------ Build started: Project: TMA04, Configuration: Debug Win32 ------
1>TMA04.obj : error LNK2019: unresolved external symbol "double __cdecl getFees(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >)" (?getFees@@YANV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) referenced in function _main
1>C:UsersEvgericDocumentsVisual Studio 2010ProjectsTMA04DebugTMA04.exe : fatal error LNK1120: 1 unresolved externals
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

View 1 Replies View Related

C++ :: Dynamically Changing Array Elements Inside Of Structures?

Feb 1, 2015

I have run across what I believe to be a syntax problem which I don't understand. I have a structure with two character array and I need to be able to change the size of those array dynamically. I have to use character arrays and I think the dot notation. I am not sure if I can use arrow notation. I can not do this problem using strings and vectors.

#include <iostream>
#include <cstring>
using namespace std;

[Code]....

View 4 Replies View Related







Copyrights 2005-15 www.BigResource.com, All rights reserved