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 {
[code].....
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 have a struct and I want to implement in with pointers and functions.
What is the corect syntax? For example:
Code:
typedef struct XYZ
{
int x;
int y;
int z;
}XYZ_t;
int func( using the XYZ_t struct)
[Code] .....
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);
[Code] .....
forget everything from before. It came out of confusion regard the supplier functions. dis_s() and read_s() the part functions work and are not any different really.
Code:
#include <stdio.h>#include <stdlib.h>
#include <string.h>
#define MPS 10 //Max Part Size
#define MSS 10 //Max Supplier Size
}
[code]....
when I run the dis_s() function it just prints out garbage until it segments. starts with a bunch of 0 and newlines until it starts printing locations on my computer...... it worked on campus with debian and I only copied it from gmail to my computer so I really don't understand whats up(im on mint).
Having a little trouble passing arguments to functions.
I wrote this simple program to get the hang of it but I'm quite stuck. I'm sure you will be able to get at what i want the program to do...
Code:
#include <conio.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <windows.h>
void menu(int HP,int Gold,int Armour);
[Code] ....
I have been struggling with pointers. I am trying to write a program that first asks a user to input a filename. It then checks if the file exists and if it does it passes a pointer to the next function. The next function then asks the user for a specific word to look for and the function will search a text file for the word and do some other operations. My problem is that I do not understand how to use the pointer returned by my first function as an input to another function.
The following code has the first function file_check() and the second function word_search() which I think the way I am declaring it is the problem.
Code:
FILE *file_check();
void word_search(FILE *);
int
main(void) {
FILE* check= file_check();
// word_search(check);
[Code] ......
I have this code where I am trying to retrieve the contents of the variable dev1 and dev2. for some reason when i compile and run I am getting 0 and 0.
Code:
typedef struct {
uint32_t x;
uint32_t y;
} sample;
void get_sample(sample *one)
[Code].....
i have a program that works, but now I am trying to get function1() to work. What it has to do is bring in the array and populate it with random letters. I don't know much about functions.
Code:
#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define maxrow 20 //defines maxrow as a constant of 20
#define maxcol 30 //defines maxcol as a constant of 30
}
[code]....
I am trying to get some confirmation about how to pass to functions. If you want to assign default values to certain parameters, and have others defined inside the body of int main(), then the parameters which will have default values go at the end of the list. Is that correct?
i.e. The following code is wrong, because we cannot leave a black in the function call on the third line of the main function. However, if we switch the prototype to void Passing (int a, int c, int b = 1); and the function definition to void Passing (int a , int c, int b) everything will be okay and we can call the function as Passing (a, c).
In brief, we cannot do this EVER:
Passing( a, , c)right?
#include <iostream>
using namespace std;
[Code]......
I've got a game engine with a line-trace collision method which returns the first object it hits. I'd like to be able to pass it a class-type so that it can ignore objects of other types.
consider this pseudo-code:
Entity* TraceEntity( const Vec3f& LineStart, const Vec3f& LineEnd, const Type atype ) {
// check collision on entities, ignore entities of type 'atype'.
// return whatever it finds
}
I'd like to do this without template classes because it will result in a significant bloat in executable size every time I decided to trace for a new entity type (I've really developed a distaste for templates for this reason)
using type_info only checks for an object's deepest subclass, so it won't work for class C : public B : public A if I'm looking for classes of type B.
I need passing some variables between functions. Here is the first part of the code which does work.
#include <iostream>
#include <iomanip>
#include <string>
using namespace std;
struct CarType {
string maker;
[Code] ....
Now the book says to take the following program and add a member function to the CarType class which prints the values of all of its data members. Add two more data members which are relevant for cars. Add the use of these data members to the program (to the assignment statements for MyCar, to the operator prompt and input inside the getYourCar function, and to the print function you have created).
Here is my code. Whenever I run it, it takes my assigned variables in MyCar and prints those instead of the one which the user is inputting.
#include <iostream>
#include <iomanip>
#include <string>
using namespace std;
using namespace std;
struct CarType {
string maker;
[Code] .....
Code:
void lexer(ifstream& inputfile) {
string line;
getline(inputfile,line);
[Code] ......
I am trying to pass input file between two functions. The code compiles but immediately upon running the program, there is a "bad cast" run time error.
My average is failing but I played and played with it and I still keep crashing.
Code: #include <iostream>
using namespace std;
void getScore(int score[], int NumGrades)
{
cout<<"How many grades do you need to enter?"<<endl;
cin >> NumGrades;
cout<<"Enter the Students Grade(s)"<<endl;
for (int i=0; i<NumGrades; i++) {
cin >> score[i];
[code].....
At first i had my int variables in global scope however i cant do the so im trying to pass my variables from my main to the void functions but cant.....
View 1 Replies View RelatedDescription: Use functions and structures to simulate storage in a warehouse
*/
#include <cstdlib>
#include<iostream>
#include<cmath>
#include<iomanip>
#include<string>
using namespace std;
struct Bin {std::string name; int Quantity;}; //create a structure for "Bin"
[code].....
I keep getting a linker error on every function. what am I doing wrong?
What this is, is a more recent assignment and my question is if my errors are directly related to passing structure addresses to functions. I've tried several syntax variations at the beginning of my loops such as this one:
while (choice != "Q" || "q")
But the loops will not run since I introduce polar to rectangular and the choice element. My last working code was rectangular to polar and all of it worked fine.
#include<iostream>
#include<cmath>
using namespace std;
//structure declarations
struct polar
{
double distance; //distance from origin
double angle; //direction from origin
[Code] ....
I am having an issue with passing an ifstream object to functions. Here is the code:
Code:
#include <fstream>
using namespace std;
void otherfunction (ifstream *ifs) {
...does stuff, like ifs->open(), then reads from the file...
}
int main () {
ifstream ifs();
otherfunction(&ifs);
}
Here is the error message:
Code: error: cannot convert ‘std::ifstream (*)()’ to ‘std::ifstream*’ for argument ‘1’ to ‘void otherfunction(std::ifstream*)’
Why can't I do that? What does "ifstream (*)()" even mean? And I don't want to change the structure of the program. I have reasons for declaring the ifstream object in the main function (because there are actually two functions that need access to the ifstream object -- neither of which is working).
Also, if I change the main function to be this instead:
Code:
int main () {
ifstream ifs();
ifstream *ifsptr = &ifs; //EDIT 2: forgot the ampersand
otherfunction(ifsptr);
}
I get the same error as above. However, if I change the main function to this:
Code:
int main () {
ifstream *ifsptr = new ifstream();
otherfunction(ifsptr);
}
I get all kinds of crazy errors about "undefined symbols for architecture _____". Here is the actual error message from my program (parseArgs is the real name of otherfunction)
Code:
Undefined symbols for architecture x86_64:
"std::ios_base::Init::Init()", referenced from:
__static_initialization_and_destruction_0(int, int)in cchumGBV.o
"std::ios_base::Init::~Init()", referenced from:
[Code] .....
I have a program that is working very well when I pass C++ vectors as arguments to my functions by reference, but I get some compilation errors when try to make a modification. I am also posting the entire program and its output below. so that you can see what is going on. I have commented out the line that causes an error.(Some of the indentation that got corrupted when I copied the code to the browser.)
This program basically calculates the coefficients of a least square polynomial and then evaluates this polynomial at artificial data points and verifies that this actually reproduces the original data within reasonable floating point error.
The function that computes the coefficients of the least square polynomial is Code: vector<double> LSPVecValued_GSL( const int, const vector<float> &, const vector<float> &); and as you can see it returns a vector by value, and this vector contains the coefficients of the least square polynomial.
There is also a function that evaluates this polynomial by accepting a vector argument by reference : Code: float evaluate_polynomial(double, vector<double>& ) ; I have also created another version of the evaluation function which accepts the same vector argument by value: Code: float evaluate_polynomial_ByValue(double t, vector<double> vec_a) ; In the program I call the first evaluation function (whose vector argument is passed by reference) by first using an intermediate vector variable containing the coefficients, and then I pass this vector as an argument to the evaluation function, as follows:
Code:
vec_a = LSPVecValued_GSL( deg, vec_x , vec_y);
for(int j=0; j< n ; j=j+20 ) {
cout<<"x["<<j<<"] = " << vec_x[j] << " ,y["<<j<<"] = " << vec_y[j] <<" , p(x["<<j<<"]) ( EVALUATED FROM REFERENCE) = "
<< evaluate_polynomial( vec_x[j], vec_a) << endl; // This version works without error
[Code] .....
As you can see above, I am also able to call the second evaluation function (the one whose vector argument is passed by value) directly by plugging in the function LSPVecValued_GSL"(...)" and this works without error, and this is a one step process, only one line of code is involved.
However, I get a compilation error (line number 12 that I have commented out above) if I try to plug in the function "LSPVecValued_GSL(...)" into the first evaluation function that expects a vector argument by reference. I tried to put a "&" in front ofLSPVecValued_GSL but this did not fix the bug.
What syntax is appropriate to use the first evaluation function (which accepts a vector argument by reference) if I want to plug in the vector-valued function LeastSquarePolynomial_GSL directly in the the first version of the evaluation function which expects a vector argument by reference?
How to properly pass both private and public variables/functions from one class to another?
View 3 Replies View RelatedI am having problems with passing my values through functions.
Here is my code:
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
void test(int**);
void test2(int**);
[Code]....
I'm having trouble with passing a character array between functions of the same class. I have a function, buildGraph, that calls function getNextLine. The getNextLine essentially just retrieves the next line of an input file and stores it into a "char line[80]". However when I try to use "line" in my buildGraph function, it has nothing in it.
Here's my code:
Class
#define NUMNODES 10
using namespace std;
#pragma once
class Prog3Graph
[Code] ....
we were given this code:
// Music Shuffle Program
// This program takes an array of strings and randomly permutes their order.
// This allows us to generate new song shuffles.
#include <iostream>
[Code]....
or are they referring to something else?
I am doing an project in SDI. I have two functions name sendtext(CString str) and displaytext(CString inr) both in different class. I have a pointer name pView to send the string str to function "displaytext". The problem is after some operations i get a text in str and i send that text to display text in the output screen i get the text and wen the second text comes to "displaytext" the former text disappears and the latest string only present. How can i display both the text in the output window on ClistCtrl class.
Code:
Void sendtext(CString str)
{
// do some operations
................
pView->displaytext(str);
}
void displaytext(CString inr) {
CListCtrl &ctlsde = this->GetListCtrl();
ctlsde.InsertColumn(1, _T("First "), LVCFMT_LEFT, 80);
int nItem;
nItem = ctlsde.InsertItem(0, inr);
}
Passing and returning character and integer arrays with functions using simple programs...use pointers if necessary
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