Im having trouble creating a struct within a struct node. the program suppose to hold students firstname, lastname, and gpa in a node therefore creating my linked list. Line 26 keeps saying that cannot convert parameter 2 from 'studentType to std::string
#include <iostream>
#include <string>
using namespace std;
struct studentType{
string firstname;
string lastname;
double gpa;
[code].....
I have a file system class that has a struct named Node declared private as so:
class FileSys{
private:
struct Node {
Node* next;
Node* prev
Node* parent;
int key;
[Code] ....
But how would I get to the Node struct? I tried to do this in the main but of course I received an error:
FileSys FS_Obj;
FS_Obj Node* T = new Node;
With errors:
Error: expected ; before Node
Error: Statement has no effect
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?
#include <stdio.h>
#define MAX_USERS 20
struct {
char ID[10];
char Name[40];
int Pos;
[Code] .....
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.
1 create a struct called complex which reprensts a complex number . both the real and imaginary compoents should be represented as doubles . ( 1 marks) .
2 write down a function called magnitude which has one parameter ( a struc complex) and a return type of double . it should return the maginude of the given parameter . ( 3marks) .
3 write a function called find_largest which has two parameter (one of type struct complex const * and the other type int) and a return type of struc complex . the two parameter represent an array of complex numbers and number of elements in that array . the function should return elements from array which has largest magnitude . this fucntion must called the magnitude function . ( 5 marks)
4 write a main function . your main fucntion . Your main fucntion should repeately prompt the user for complex number , storing them in an array. you should continuing reading in complex number until the user enters in both componets , at this point you should stop . you should not make an assumptions how many complex number the user will enter , ( i.e use realloc) after reading in complex numbers from the user you should print out real and imaginary components of the complex number with the largest magnitude.
Code:
#include<stdio.h>
struct complex {
double real;
double imag;
[code]....
My address book will be simple, and the thing's that I'm expecting to use in it are :
Pointers, Linked Lists
Malloc
Structs
Typedefs
Makefile, header file
Putting functions into different program files
I have started the program trying to create a struct, and getting it working with a couple of entries before going onto user input and splitting it up.
Code:
#include <stdio.h>
#include <stdlib.h>
int main(void) {
// Struct type address book. Just a name, a number and a pointer
[Code] .....
I'm a bit lost at this point... My knee jerk thought is to create a for loop, and cycle through the list.
I'm not sure how this would apply to this though? Without using the familiar type of print loop such as :
Code:
for (i = 0; ;i++) {
printf("%i
", array[i];
}
I'm thinking that I need to create a temporary struct that can be used to assign the value of the next struct in the list, and then somehow print from that....
I'll try and write the logic out :
while temp != NULL (The last node value is assigned NULL to show us where the end of the list is)
create a temporary pointer that can be used to keep track of where we are in the list.
print out the current entry name and number
then assign the temp pointer value to the * next of the current struct. So if we are in entry1 the *next should be the address of entry 2.
Print out entry 2 name and number, assign entry 2 next to the temp value.
"
#include <stdio.h>
struct datastructure {
char character;
};
void function(struct datastructure** ptr);
[Code] ....
These codes give these errors:
error: request for member 'character' in '* ptr', which is of non-class type 'datastructure*'
error: request for member 'character' in '* ptr', which is of non-class type 'datastructure*'
These errors are related to
"
*ptr->character='a';
printf("Ptr: %c",*ptr->character);
"
I want to access "character" data inside the structure "trial" by a pointer to pointer "ptr" inside function "function",but I couldn't find a way to do this.
I just read and have known for a while that classes are private (members and inheritance) by default and structs are public. But my question then comes what if.. a struct inheriting from a class or a class inheriting from a struct?
View 3 Replies View RelatedCode:
#include <stdlib.h>
#include <stdio.h>
typedef struct characterNode {
char c;
characterNode *prev;
characterNode *next;
} CharacterNode;
[Code]...
What's wrong with this? People told me that casting malloc was bad, but I don't understand what struct cn *temp is doing.
Also, could I create something like:
Code: typedef CharacterNode *CharacterNodePtr To be a pointer to my struct type? Why would that be beneficial?
So why does this not work? As an example:
struct example {
int x; int y;
};
int main() {
example variable;
variable.x = 1;
variable.y = 2;
map<example, int> something;
something[variable] = 3;
return 0;
}
And I get a very long error message from the compiler. I tried using an enum as the key as well and that worked just fine, but I guess that's just the same as having an integer as the key. But anyway, what's the problem with this? Is there any way to make it work?
how can I call and print the Pointer:
ptr->address
Code: #include<stdio.h>
struct account {
int address;
int value;
[code]....
So i create a simple structure,that has a firstname, lastname, age, dateofbirth.I would like it if i type what I am searching for print out there is one or not.But i have some trouble with equals(in array).. i type in the same "keresettnev" as "tanulok[i].Firstname" but it thinks not the same. (it works with age..)
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct student {
char *Firstname[40];
char *Lastname[40];
int age;
[Code] ....
I am using Beej's Guide to Network Programming Using Internet Sockets. I'm just curious why I need to zero out the rest of the struct?
Code:
int main(){
int sockfd;
struct sockaddr_in my_addr;
sockfd = socket(AF_INET, SOCK_STREAM, 0);
[Code].....
Code:
#include <stdio.h>
struct database {
int id_number;
int age;
float salary;
[Code] ....
When I compile, I get an error:
test.c|18|error: incompatible type for argument 1 of 'printf'|
note: expected 'const char *' but argument is of type 'float'|
I thought employee.salary is a float but the compiler expected 'const char'. How do I make this work?
I am working on a program which uses external hardware to acquire data. we have the option to use hardware from two different companies, each with it's own driver. However both do the same job. My program is meant to read data packets which are structured as:
typedef struct _data {
DWORD ID;
BYTE bf;
BYTE bd;
BYTE bData[8];
DWORD bt;
} data;
Now both the companis use the same data structure, but the first has defined the structure, let's say, as:
typedef struct _dataX {
DWORD ID_X;
BYTE bf_X;
BYTE bd_X_;
BYTE bData_X[8];
DWORD bt_X;
} dataX;
[code].....
I am programming my software so as t allow the customer to use the hardware of their choice. Simply select the card they are using and our program should be able to take care of the rest of stuff. I am using #ifdef directives to include the header for the corresponding hardware dll. Now I want to define my own data struct of the type:
typedef struct _dataMY
{
DWORD ID_MY;
BYTE bf_MY;
BYTE bd_MY_;
BYTE bData_MY[8];
DWORD bt_MY;
}
[code]....
and when I use _dataMY.ID_MY .. it should directly be able to see if it is _dataX.ID_X or _dataY.ID_Y, based upon the directive I have used earlier.
I've been working on a path-tracer for some time, and all along I've used structs instead of classes for vectors and matrices. Today I changed all of them to classes instead, changing none of the actual function bodies themselves, and the results were miserable to say the least.
Here's a render form before the change: [URL] ....
And here's the same render after: [URL] ....
Why this is happening, considering that none of the actual function-bodies have been changed, except for what little is needed to make the change from class to struct.
Suppose I have a struct with 20 members. I want to assign each of those structs with values. Instead of accesing by explicit convention, i.e.:
Code: struct.member1 = 1;
struct.member2 = 2;
...
...
...
struct.member20 = 6;
Is there any way to encapsulate it in a for loop and use an iterator variable to indicate the member? i.e.:
Code: for (int i = 0; i < 20; i++)
struct.i = i;
The above is pseudocode but Im sure you get what Im trying to do?
So this is the last part of a program I've been working on for four weeks now. This question may be a tough one considering the amount of files included in the program.
The program is to read in a file of requests between two cities, read in a file of flights and cities that occur between the cities. It then checks to see if there is a path between the flights and output an itinerary. I have the correct itinerary outputting, but when attempting to output the associated flight number and price according to the city, I am getting odd data. How can I output the correct flight number and price associated with each flight on the itinerary.
I'll post out the output I am currently getting and the section where I am outputting the data. I'm sure I'll need to post more files so the program can be understood.
Don't want the code done for me, just a point in the right direction! I don't want to let this program defeat me!
Output: Code: Request is to fly from Atlanta to San-Diego.The flight itinerary is:
Flight # From To Cost
10 Atlanta Chicago $134529069
10 Chicago Miami $134529069
10 Miami Dallas $134529069
10 Dallas San-Francisco $134529069
10 San-Francisco San-Diego $134529069
This function finds a path between cities. Code: bool flightMap::IsPath(string originCity, string destinationCity){
StackClass aStack, bStack;
flightStruct flightRec;
string topCity, nextCity;
bool success;
int index = 0;
[Code].....
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):
header.h Code: #ifndef lab_6b_7b_Header_h
#define lab_6b_7b_Header_h
//header file intiating other headers
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct{
[code]....
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:
Code:
#include <stdio.h>
#include <stdlib.h>
typedef struct BOOK
{
int* price;
} Book;
[Code] ....
Code:
/*
* Instruction_t - stores a specific instruction
*/
typedef struct
{
[code]....
I have a problem. When I run my program (which contains this), through gdb, I can see that burstTime does have a value ( such as 1, 3, 15, etc).But when I dequeue from my list, instruction->burstTime suddenly equals zero!
Is it common practice to package methods with other elements(string-s, int-s, float-s, array-s...) of struct?
Than struct acts as a class or is acting similar to class and that have no sense to me? I am new to OOP .
I am trying to write a structure to a file. Example say the structure has two variables x and y . I want to write a function which modifies these variables and stores the modified version on a file. Such that next time I call the function . it has the values from the previous write. Here's an example of my code .
Code:
// initialize the structure struct->x = 0, struct->y = 0
File *fp = fopen("filename", "r+");
struct MYSTRUCT mystruct = (struct MYSTRUCT*)malloc(sizeof(MYSTRUCT))
//check
fread (mystruct, sizeof(MYSTRUCT), 1, fp);
// do some calculations.
fwrite(mystruct, sizeof(MYSTRUCT), 1, fp);
fclose(fp)
//return some value
}
The problem is that each time I run the program it shows the initialized value of the variables and not the value from last write. I guess the write isn't successful because when I open in w+ mode. i get the error file could not be opened and then i have to delete the file and re create it....
I am a bit unsure about what this piece of code aligning a struct to a page is trying to achieve.
Code:
#define PAGESIZE 1 << 12
typedef struct __attribute__((aligned(PAGESIZE))) x86_pagetable {
x86_pageentry_t entry[PAGETABLE_NENTRIES];
} x86_pagetable; It is an piece of code from an educational operating system WeenyOS.
What is the essence of aligning a struct to a page?
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.
FIRST MICROPROCESSOR
Code:
extern struct i2c_data * TX_Data;
extern struct i2c_data TX_Data_1;
extern struct i2c_data TX_Data_2;
}
[code]....
how to print struct from another function? let's say I have code this way
Code:
struct student{
int id // simple example
};
main(){
modify_data(); // calls the function.
}
[code]....
