C++ :: Write Prototype Of A Member Function To Overload Insertion Operator
Apr 10, 2014
Consider the class specification below. Write the prototype (i.e. header) of a member function to overload the insertion operator (i.e. <<). The << operator is to output the data members of an instance of class StudentTestScores into an output stream. Your definition should allow for chaining of output operations (e.g. cout << x << y; where x and y are of type StduentTestScires).
#include <string>
using namespace std;
class StudentTestScores{
private:
string studentName;
float *testScores; // used to point to an array of test scores
int numTestScores; // number of test scores
[code]....
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Mar 22, 2013
I'm doing a refresher for C++ and have gotten to operator overloading. I'm trying to perform an operator overload with the insertion (<<) operator, but I have encountered a problem.
Here's my class [In a header file "Shinigami.h"]
#include<string>
namespace K{
class Quincy;
class Shinigami{
friend std::ostream& operator<<(std::ostream&, const Shinigami&);
[Code] .....
If the operator function is a friend of the 'Shinigami' class, why doesn't it recognize any of it's private members? I need it to be in this file because I'm doing a bit of association with the 'Quincy' class.
I thought it was the namespace, but I included that.
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Aug 23, 2014
Say I have a class that requires dynamic allocation to implement a few of the operators. Take "+" for example; I need to create a new object to hold the sum of the two parameters whose size is not known at compile time.
I'm pretty sure the standard way to indicate a failure inside the overloading function would be to throw an exception. However I am currently involved in an embedded(ish) project where the spec. says no exceptions are to be used.
I think I have 2 options:
1. Return an "invalid" object (with a flag indicating an error has occurred) and check for this after each operation.
a = b + c
if (a.err)
// handle error
or
2. To forsake operator overloading entirely and think up a new way of doing things where all functions that involve dynamic allocation can return error codes. but this seems rather terrible too as I may end up with something like:
objA a
if (add(&a, b, c) == -1) // assuming b and c are initialized before this snippet starts
// handle error
Is there a number 3 that I haven't thought of? It seems that not allowing exceptions is fairly common even in the non-embedded world [URL] so how is this normally done? or is operator overloading usually avoided when exceptions are not allowed?
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Dec 26, 2014
I want to overload prefix and postfix increment(++) operators with friend function. I also have to use the constructors for this. How can I do this? in C++
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Nov 30, 2013
I defined a virtual class and three other classes based on it. I want to use them like this:
int main() {
Dirichlet_t D;
Neumann_t N;
Cauchy_t C;
PDEBoundary_t * B1=& D;
PDEBoundary_t * B2=& N;
PDEBoundary_t * B3=& C;
[Code] .....
but I got two major errors
1: "object f abstract type is not allowed" error.-----why not?
2: "the derived class must implement the inherited pure virtual method"-----Did't I?
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Apr 3, 2013
why can't << operator be overloaded as a member function is it because that is the way c++ is written and you just can't or is there another reason because I'm confused.
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Dec 26, 2014
I want to create a program that shows the total of 2 subjects & percentage of student using binary operator overloading with member function in C++.
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Jul 10, 2014
Here's my question. I'm coding a basic Linked List class (for the purpose of understanding and having fun, I know about STL), LList.
I have overloaded the [] operator so it returns the data of the index-th node in the list, for example, if I code
LList x;
....
cout<<x[5];
it prints the data of the 5th node in the list (for fun I decided to index from 1 to infinity).
My question: Now I want to be able to assign the value to the index-th node data, using [] and =, for example, I want to be able to write:
LList x;
.....
x[5] = 121;
How can I do that?
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Apr 24, 2014
How would i be able to overload a multiplication operator that if, in the main example(0, 5, 0) * example (0, 5, 0) is given, it gives me 25?
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Sep 27, 2014
We're trying to overload the delete[] operator with specific arguments. Which is the right way to call it? We use the GNU compiler and obtain compiler errors with all of these samples:
#include<iostream>
using namespace std;
typedef unsigned int P;
[Code]....
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Apr 30, 2014
I'm trying to come up with the union of two Vector ADT bags, so I have to overload the '+' operator, but I'm getting a bunch of error messages saying:
VectorBag.cpp: In instantiation of ‘VectorBag<ItemType> VectorBag<ItemType>::operator+(VectorBag<ItemType>) [with ItemType = int]’:
proj2.cpp:161:42: required from here
VectorBag.cpp:81:24: error: no match for ‘operator[]’ (operand types are ‘VectorBag<int>’ and ‘int’)
newBag.add(anotherBag[i]);
^
Here is the function to overload the operator:
template<class ItemType>
VectorBag<ItemType>
VectorBag<ItemType>::operator+(VectorBag<ItemType> anotherBag) {
VectorBag<ItemType> newBag;
for (int i = 0; i < anotherBag.getCurrentSize(); i++)
newBag.add(anotherBag[i]);
}
The add() function is pre-defined by me somewhere else in the code. It basically does push_back().
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Nov 12, 2013
i am doing some practice problems and i can't seem to figure out how to do this. basically we have a students number of test scores, then the name followed by the scores they have in a text file. Then we have to make a class with a constructor, copy constructor, destructor, and overload the = operator and the input and output operator. Are we suppose to call the text file in the input overload operator?
Here is what i have so far.
This is my header file.
#ifndef STUDENTTESTSCORES_H
#define STUDENTTESTSCORES_H
#include <string>
#include <iostream>
using namespace std;
class StudentTestScores{
private:
string studentName;
[Code]...
i am 100% sure the overloading the input is wrong
here is the implementation of the constructor copy constructor and desctructor
#include <iostream>
#include "StudentTestScores.h"
using namespace std;
StudentTestScores::StudentTestScores(string name = "", int numScores = 0)
{
studentName = name;
numTestScores = numScores;
if (numScores <= 0)
testScores = NULL;
else
[Code]...
and here is the notepad file
3
Justin Bieber491.469.184.681.081.5
Miley Cyrus380.080.090.083.3
Kim K490.575.661.481.677.2
The program is suppose to use all the information and read from the notepad and output the exact things as the notepad file
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Nov 10, 2013
struct Node {
int entry;
Node *next;
Node(); //1
Node(int item, Node *link = NULL); //2
[Code] .....
Implement: 1 2 3 4 5
and overload operator <<, >>, =
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Jul 27, 2012
/*using GENERIC_COMMAND* A; as volatile generates error. but here i have to use union object as volatile i.e. volatile GENERIC_COMMAND* A; */
#include <iostream>
using namespace std;
typedef unsigned int uint32_t;
typedef unsigned long long uint64_t;
union GENERIC_COMMAND {
[Code] .....
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Oct 17, 2012
I have a basic vector/point class where I've overloaded a bunch of arithmetical operators:
Code:
#pragma once
class point {
public:
point() {
}
point(float p_x, float p_y, float p_z) : x(p_x), y(p_y), z(p_z)
[Code] ...
I can use it fine like
Code:
point p(50,50,50);
point q(50,50,50);
point t = p * q + q;
However when I put this point type into a struct and try to access the members after passing it through by const reference:
Code:
struct sextic {
point a,b,c,d,e,f,g;
};
inline static sextic sexticDifference(const sextic &p_sextic1, c
[Code] ....
This gives me an "operator not defined" error for compilation.
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Mar 30, 2013
[URL] ..... Prototype is commented.
[URL] ..... Prototype is included.
both give the correct output. Why?
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Aug 25, 2014
#include<stdio.h>
#include<conio.h>
#include<math.h>
void main() {
int i=1,j=2;
float k,l=1.5;
[Code] ...
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Jan 9, 2015
The task is to use the assignment operator of a class, but change all the data except certain ones. For example, below we are to assign all Person data of 'other' except for 'name' and 'ID':
#include <iostream>
#include <string>
struct Person {
std::string name;
int ID, age, height, weight;
[Code] .....
Name = Bob
ID = 2047
Age = 38
Height = 183
Weight = 170
Name = Frank
ID = 5025
Age = 25
Height = 190
Weight = 205
Bob pretends to be Frank, but keeps his name and ID.
Name = Bob
ID = 2047
Age = 25
Height = 190
Weight = 205
But I think the way I did it is pretty lousy (note the wasted steps changing the name and ID only to revert them back? So the ideal solution should require no wasted steps, unlike the method above, and changes to what the exclusions should be should be in only one place (not two like above). Of course, we assume that Person shall have many, many data members (and constantly increasing), so that simply defining Person::operator= (const Person& other) to handle all data except for 'name' and 'ID' is out of the question.
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Mar 30, 2013
The function im having problems with takes an array where each element is an array of unsigned chars i.e. octals representing a bitmap of one of 95 ASCII code characters and searches through this two dimensional array looking for a match for a predetermined of array of unsigned chars i.e. the bitmap of a predetermined char. If we find the char the function outputs the index in the two-dimensional array where each elem. is an array of octals ELSE it return -1 i.e. when the char is not found.
I have 2 files, one .cpp, the other .h. There is a function named find_char. See INPUT and OUTPUT on line 48 in .cpp file.
The exception im getting is: font2.cpp:23:45:error: invalid conversion from unsigned char to unsigned char(*)[5]
The input type specified for my function prototype corresponding to find_char. If I put just unsigned char it doesn't fix the problem because it's an array parameter i.e. like a call by reference. I've lead myself to believe that the array variable contains a pointer to the first value in the array and so I've made function prototypes that work with a T* i.e. a pointer to type T. Making the function prototype argument unsigned char* i.e. a pointer to unsigned char simply gives me the exception: "invalid conversion from unsigned char to unsigned char*". When I have the argument be 'unsigned char' I get undefined reference to find_char(unsigned char). URL.....
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Mar 29, 2014
This is my code:
#include<iostream>
#include<string>
using namespace std;
int bin2dec(const string binarystring); // Declaration of bin2dec prototype with one string parameter
int main() {
cout << "Enter Q to terminate program.
[Code] .....
Right now the code is in the form of a 'const string binarystring' and were supposed to be able to use 'const char binarystring[]' and for some reason whenever i try to switch it i run into problems when referencing the main function to the int bin2dec(...) function.
I wanted to know if theres a simple way to switch the prototype to an array type of function with [] without changing the entire code.
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Aug 20, 2014
Let's first take the following class prototype:
#include <ctime>
#include <iostream>
#include <sstream>
#include <string>
#include <fstream>
class Debugger;
class Debugger {
[Code] ....
My question is regarding the GetCurrentDebugLevel function above. Ideally I would like to use just one function to get the current debug level of the class, the std::string form would be used to save the "debugging level" in a settings file and the enumerated version would for evaluation purposes throughout the program.
My question is if implementing function prototypes by return value the best way to go or should I do something else?
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Apr 23, 2014
We can initialize normal function prototype's parameters with zero like this:-
void output(float = 0.0, int = 0);
or
void output(int = 0, int = 0, double = 0.0);
But how do you do the same for a pointer array or simply an array?
Assume that second parameter has to be an array.
I have tried the following and it does not work:-
void output(float = 0.0, int = 0);
void output(float = 0.0, *int = 0);
void output(float = 0.0, int* = 0);
void output(float = 0.0, int[] = 0);
void output(float = 0.0, int []);
But if I skip the default declarations altogether, it works.
like:
void output(float, int []);
or
void output(float, int*);
how can I do it by explicitly writing zero, just like the first cases?
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May 22, 2013
#include<iostream.h>
#include<conio.h>
int main() {
setcolor(BLUE);
setbkcolor(yellow);
cout<<"the text in blue colour with yelow background";
getch();
return 0;
}
it keeps returning the same error always in my turbo c++ compiler . What is the correct program for changing background colour and text colour ...
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Feb 18, 2013
I'm trying to create a function that allows insertion anywhere in a linked list...here is what I have so far but am a bit confused on where to go from here
Code:
void llAddAtIndex(LinkedList** ll, char* value, int index) {
LinkedList* newNode = (LinkedList*)malloc(sizeof(ll));
newNode = *ll;
LinkedList* prevNode = (LinkedList*)malloc(sizeof(ll));
[Code].....
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Jan 15, 2015
This program I'm working on accepts an array size from the user, prompts the user to store that many integers, sorts them from smallest to largest, and then searches for duplicates with a simple for loop. The ultimate goal of the assignment was to display duplicates in an array, and the rest of the functions are just how I decided to reach that goal.
Anyway, my program crashes if I choose an array size larger than 7. It sorts and displays duplicates perfectly with 7 or fewer arguments.
The exact moment it crashes is after I enter the final value it prompts me for, so it appears my inputsize() function and my inputarray() function are working, and the error may be in the arrsort() function. Code is below:
Code:
#include <stdio.h>
int funcinputsize(int);
void funcinputarray(int [], int size);
void funcarrsort(int [], int size);
void funcdupe(int [], int size);
[Code] ...
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Dec 16, 2012
In my MFC, CMyPorpertyPageDlg is derived from CPropertyPage. How to access its member function from a nonmember function in the same CPP file?.
void Non_Member_Get_PorpertyPage()
{
CMyPorpertyPageDlg* pPageDlg = ....
}
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