For my default constructor I need to set an array of strings to null and the size variable to 0. Here is my code for that
DynamicStringArray::DynamicStringArray() {
*DynamicArray[]=NULL;
size=0;
}
When I try and compile it I get an "expected primary expression before ']' token" error.
I am trying to print the array of string using this code but the compiler is printing null in the output:
The code is as follows:
char *arr[10];
int i;
for(i=0;i<10;i++)
scanf("%s",*(arr+i));
for(i=0;i<10;i++)
printf("%s
",*(arr+i));
VS 2012 / Windows 7 64 bit
class
class myclass {
public:
myclass(){/*stuff here*/}
myclass(int* p) {MyPointer = p; myclass()}
[Code] ....
it works until the myclass(int* p) calls myclass()
then the MyPointer will become CCCCCCCC (NULL value)!
is there a way to stop the second constructor from resetting the pointer value to null?
How do I set the size of a member array via the class constructor if I know the size at compile time. I can do this with templates, see below, but this leads to code bloats, I think.
So one class declaration but objects with different array sizes.
Can't use constexpr.
Can't use STL.
Can't use new.
#include <iostream>
using namespace std;
template<int T>
class MyArray {
private:
int array[T];
public:
int getSize()
[Code] ....
This problem is best explained by looking at its output below. I stored 15 different values but when retrieved some are wrong.
#include <iostream>
using namespace std;
class A {
public:
int ** pointer;
[Code] ....
I need to store and retrieve the 15 different values correctly. How to solve this? The main thing is, I need to store the pointer in class A objects.
First I wrote a Binary-tree class to draw a binary tree on the window. The nodes were small circles. Then I become wanted to change the shape of the nodes from circles to triangles by another class, Binary-tree-derived which is derived from Binary-tree class. I wrote the below code to do the job but I get two errors about constructors. First, code:
/* The binary-tree class, one of the topics that has been said in Programming Principles and Practice using C++ book by Biarne Stroustrup.
This code is written by R Abbasi (s.rabbasi@yahoo.com) */
#include <Simple_window.h>
[Code].....
Errors are:
Error12error C2512: 'Binary_tree' : no appropriate default constructor availablec:userscsdocumentsvisual studio 2012projects est_1 est_1 est_1.cpp91
13IntelliSense: no default constructor exists for class "Binary_tree"c:UsersCSDocumentsVisual Studio 2012Projects est_1 est_1 est_1.cpp91
How do you write a default constructor?I need to use a default constructor that will initialize the data members:
- salesPerson to “Unknown”
- noOfWeek to 13
- amount to point to an array of thirteen 0.00s.
This is my weeklysales class
class WeeklySales {
char* salesPerson;
double* amount; // Pointer to an array
int noOfWeek; // Size of the array
};
Here's my attempted code:
//default constructor
WeeklySales (){
salesPerson="Unknown";
noOfWeek = 13;
amount = 0.00;
}
A compiler auto created default constructor is called a synthesized default constructor. It will initialize the built-in members to 0 or not depends on where the class object is defined? if I define a class
class point{
public:
double x, y;
};
if I define point point1; in global scope then point1.x and point1.y will be initialized to 0, if I define point point2; in a local scope, then its x and y won't be initialized? If it is like this, then I believe if there are built-in type members in a class, then the synthesized default constructor is almost useless!
I have a question about the default constructor.
To my best understanding, the compiler will provide me with a deafult constructor only if there are no any user defined constructors, at all. Now consider the following code:
Code: class MyClass
{
private:
int m_data;
public:
MyClass(int init):m_data(init){cout<<"Ctr called"<<endl;}
[Code] ....
How is it that suddenly, there is a default constructor?
trying to practice the object-oriented part of it by converting my java programs into c++. I believe I understand the concepts of a header file and declaring the functions in the .cpp files. I keep getting this "Undefined reference to NamedStorm::NamedStorm()" error.
NamedStorm.h
#ifndef NAMEDSTORM_H
#define NAMEDSTORM_H
#include <string>
#include <iostream>
// NEVER use using namespce in header, use std instead.
using std::string;
[code]....
Im trying to create two box in this program using the default constructor. When i call to try and display the info, it says that x, y, and z are not declared in this scope. i wanted to have the user cin the length, height, and width using the void setBox function.
#include<iostream>
#include<string>
#include<cstdlib>
using namespace std;
class Box{
public:
[code]....
In C++ if no user defined constructor is provided for a class the compiler automatically provides a implicit default constructor.
An implicit default constructor is equivalent to a default constructor with no parameters and no body ?
So what is the use of a implicit default constructor provided by the compiler, if it is not going to do anything ?
i tried running my code and i keep getting the error "call to implicitly-deleted default constructor of 'node'. My code is as follows
//.h file
typedef struct node * point
struct node{
string data;
node *next
}
[code]....
I get the error at the line "ptr1 = new node;" I tried putting a default constructor for my node struct and that fixed the problem but a new problem arises. It states that i have a linker error after i compile it with a default constructor.
class Date
Date(int=1, int=1, int=1990);
class Person
Person(string="", string="", Date=NULL);
class RealEstateAgent:Public Person
RealEstateAgent(string="",string="",Date=NULL,Date=NULL,int=NULL, double=0.0);
}
[code]....
how can I assign default values with Customer object and RealEstateAgent?
I was making a template list class, and using it to make list of objects of my own class.It works fine with integers, but not with other classses.
template <typename T>
class CList {
public:
struct Node {
T data;
Node* next;
[code]....
While in AddElement(), it gives error - Default constructor not available.
template<typename T>
bool CList<T>::AddElement(T t) {
bool result = true;
if (head == NULL) {
[code]....
what is wrong here.
How do I insert a array size as variable?
View 5 Replies View RelatedFor example, I have an empty vector of integer. If I keep calling push_back on vector, is it going to be out of memory?
View 8 Replies View RelatedThe WinAPI has a struct like this for raw input:
Code:
typedef struct tagRAWINPUT { RAWINPUTHEADER header;
union {
RAWMOUSE mouse;
RAWKEYBOARD keyboard;
RAWHID hid;
} data;
[code]...
The definition of the struct doesn't show it but the documentation says that bRawData is variable length. sizeof(RAWINPUT) will not be the correct size when the data field is of RAWHID type so how do you allocate a variable with automatic storage type that has the right size for the entire struct? You can get a header that has the size for the entire struct but how do you actually allocate storage space for the data without using malloc? I've seen some example code that used a char array but that violates aliasing rules and there are also alignment issues with that approach.
I am wondering how I could make an array which contains arrays, but with a variable size.My first try..
Code:
int array[][] = {{1}, {2}};
But this isn't proper
I have a function like this
void foo( int i) {
...
uint8_t buf[ i];
...
}
And I don't understand why the compiler is not complaining... I'm using g++ -c -g -Wall to compile ....
I believe that everything is fine except that I can think of the condition can be inserted inside the parentheses ..
#include <iostream>
using namespace std;
int main() {
int i=0, k=0;
char *string_n, **matrix, temp;
[code].....
I am new to C. I've been trying to use C to code some statistical functions originally coded in R. I've encountered an interesting phenomenon. In the function foo1, I declared the array v1v2b using an actual value 1999000. The function runs fine when I call it in R.
Code:
void foo1(double *x, double *y, int *nsamp){
int i, j, k, oper=2, l;
double* v1v2=malloc(sizeof(double)*((*nsamp)*(*nsamp-1)/2 + 1));
outer_pos(x, y, nsamp, &v1v2[0]);
double v1v2b[1999000]; //<-------HERE
for(i=1; i<= 1999000]; i++){
v1v2b[i-1]=1;
} }
However, in foo2, I first create an integer variable called index, and store the value 1999000 in it. I then use it to initialize the same array. When I tried calling this function in R, it either led to a stack overflow error, or completely crashed R.
Code:
void foo2(double *x, double *y, int *nsamp){
int i, j, k, oper=2, l;
double* v1v2=malloc(sizeof(double)*((*nsamp)*(*nsamp-1)/2 + 1));
[Code] .....
how to insert a variable for the size of array and prompt user to insert the elements for the array?
View 13 Replies View RelatedI am supposed to use scanf() for this assignment to limit the number of charachters in the string. However, I cant seem to get it to work in either scanf() or fgets().
// main.c
// Lab_Ccode_1 + extra credit = input validation.
//
// Created by IanMiles on 1/28/15.
[Code]....
In a project I am working on, I have to initialize a window and pass it as a parameter to another constructor, but before the window is initialized, it is passed as a parameter thus causing an error. Here is some code :
Game::Game()
: mWindow(sf::VideoMode(640, 480), "SFML Application", sf::Style::Close)
, mWorld(mWindow) //<---- right here is where the mWindow variable needs to be passed
{
//...
}
Is there a way to make this work???
how do I tell the if statement to output this error message 'exceeded the maximum amount of characters' that has its characters stored in an array using c-style string?
[INPUT] The cat caught the mouse!
[OUTPUT] Exceeded the maximum amount of characters (max 10)
#include<iostream>
#include<string>
[Code]....
