I´ve got this CRac class and it´s giving me some problems with its members.
//Definition TAD CRac.hpp
#ifndef CRAC_H
#define CRAC_H
namespace bblRac{
struct Racional{
int num, denom;
};
class CRac{
public:
CRac();
void read();
void asignarVal (const CRac& otroRac);
void write();
void add(const CRac& otroRac)const;
private:
Racional rac;
void simplif();
}; //End of class CRac
} //End of namespace bblrac
#endif
In a ccp file I have
#include "CRac.hpp"
using namespace bblRac;
void CRac::add(const CRac& otroRac)const{
CRac res;
res.num= rac.num + otroRac.num; //line 98
res.denom= rac.denom + otroRac.denom;
}
And when I run it, the output is
CRac.cpp:98: error: ‘class bblRac::CRac’ has no member named ‘num’
CRac.cpp:98: error: ‘const class bblRac::CRac’ has no member named ‘num’
CRac.cpp:99: error: ‘class bblRac::CRac’ has no member named ‘denom’
CRac.cpp:99: error: ‘const class bblRac::CRac’ has no member named ‘denom’
I have tried to fix it with the pointer this, but it continues giving the same mistake..
Thank you!
This will fix it.
#include "CRac.hpp"
using namespace bblRac;
void CRac::add(const CRac& otroRac)const{
CRac res;
res.rac.num= rac.num + otroRac.rac.num; //line 98
res.rac.denom= rac.denom + otroRac.rac.denom;
}
Your CRac class contains a Racional member variable, num and denom are not members of CRac.
res.rac.num = whatever;
otroRac.rac.num = whatever;
Please look your code over before you hit copy/paste into StackOverflow.
Related
I do understand why the following would be a problem if no namespaces were used. The call would be ambiguous indeed. I thought "using stD::swap;" would define which method to use.
Why does it work for "int" but not a "class"?
#include <memory>
namespace TEST {
class Dummy{};
void swap(Dummy a){};
void sw(int x){};
}
namespace stD {
void swap(TEST::Dummy a){};
void sw(int x){};
class aClass{
public:
void F()
{
using stD::swap;
TEST::Dummy x;
swap(x);
}
void I()
{
using stD::sw;
int b = 0;
sw(b);
}
};
}
This is the error message:
../src/Test.h: In member function ‘void stD::aClass::F()’:
../src/Test.h:26:9: error: call of overloaded ‘swap(TEST::Dummy&)’ is ambiguous
swap(x);
^
../src/Test.h:26:9: note: candidates are:
../src/Test.h:17:6: note: void stD::swap(TEST::Dummy)
void swap(TEST::Dummy a){};
^
../src/Test.h:10:6: note: void TEST::swap(TEST::Dummy)
void swap(Dummy a){};
^
I thank you very much in advance for an answer.
This line is using argument dependent lookup
TEST::Dummy x;
swap(x);
So it will find both void stD::swap(TEST::Dummy) as well as void TEST::swap(TEST::Dummy) because x carries the TEST:: namespace.
In the latter case int b = 0; the variable b is not in a namespace, so the only valid function to call would be stD::sw due to your using statement.
I am pursuing some interest in c++ programming by way of self instruction. I am working on some basic stuff for now and am currently having issue getting my classes talking/instantiated?.
I am trying to get my main cpp file to compile alongside a header and call to some class functions through the main using a more efficient command method.
I am stuck and would appreciate some help. I will include both files. I am just trying to get a return value from the header by calling the function.
error:
main.cpp:6.21 error: cannot call member function 'void myClass::setNumber(int) without object
the code works when compiled with the main, so it is something with the 'scope resolution operator' i think. First is main.cpp
#include <iostream>
#include "myClass.h"
using namespace std;
int main(){
myClass::setNumber(6);
{
return number;
}
}
Then my header file myClass.h
// MyClass.h
#ifndef MYCLASS_H
#define MYCLASS_H
class myClass {
private:
int number;//declares the int 'number'
float numberFloat;//declares the float 'numberFloat
public:
void setNumber(int x) {
number = x;//wraps the argument "x" as "number"
}
void setNumberFloat(float x) {
numberFloat = x;
}
int getNumber() {//defines the function within the class.
number += 500;
return number;
}
float getNumberFloat() {//defines the function
numberFloat *= 1.07;
return numberFloat;
}
};
#endif
Any help?
The error message says everything:
cannot call member function 'void myClass::setNumber(int)' without object
You need to create an object first:
myClass obj;
then call the class method on that object:
obj.setNumber(6);
The value 6 will get assigned to the number field of the obj variable.
Hi I am making a simple stack class in C++ and am new to C++. I am having a few errors that I cannot figure out what they mean. Some help would be greatly appreciated! Here is my code:
Stack.h
#ifndef SStack
#define SStack
#include <cstdlib>
#include <string>
class SStack
{
public:
// Constructor
SStack( int cap);
// Copy Constructor
SStack( const SStack& s );
~SStack( );
void push ( const std::string& s);
std::string& pop ();
std::string& top () const;
bool IsEmpty () const;
int size() const;
int getCapacity() const;
// NONMEMBER FUNCTIONS for the bag class
// Precondition: s1.size( ) + s2.size( ) <= s1.Capacity.
// Postcondition: The stack returned is the union of s1 and s2.
SStack operator +(const SStack& s2);
private:
int Capacity; // Capacity is the maximum number of items that a stack can hold
std::string *DynamicStack;
int used; // How many items are stored in the stack
};
#endif
Stack.cpp
#include "SStack.h"
#include <string>
#include <cstdlib>
#include <iostream>
using namespace std;
class SStack
{
public:
void SStack(int cap){
DyanmicStack = new string[cap];
Capacity = cap;
used = -1;
}
void SStack(const SStack& s){
DyanmicStack = new string[cap];
}
~SStack( ){
delete(DynamicStack);
}
void push(const string& s){
DynamicStack[used] = s;
used++;
}
string& pop(){
if(used==-1){
cout << "Error stack is empty";
return " ";
}
else{
used--;
return DynamicStack[used+1];
}
}
string& top () const{
if(used==-1){
cout << "Error stack is empty";
return " ";
}
else{
return DynamicStack[used];
}
}
bool isEmpty(){
return (used==-1);
}
int size(){
return (used+1);
}
int getCapacity(){
return Capacity;
}
private:
int Capacity; //How much the stack can hold
string* DynamicStack;
int used; //objects in the stack
};
And here are the errors:
SStack.h:11: error: expected unqualified-id before ‘int’
SStack.h:11: error: expected `)' before ‘int’
SStack.h:13: error: expected unqualified-id before ‘const’
SStack.h:13: error: expected `)' before ‘const’
SStack.h:14: error: expected class-name before ‘(’ token
SStack.h:25: error: ISO C++ forbids declaration of ‘operator+’ with no type
SStack.h:25: error: ISO C++ forbids declaration of ‘s2’ with no type
SStack.h:8: error: an anonymous union cannot have function members
SStack.h:31: error: abstract declarator ‘<anonymous class>’ used as declaration
SStack.cpp:11: error: expected unqualified-id before ‘int’
SStack.cpp:11: error: expected `)' before ‘int’
SStack.cpp:17: error: expected unqualified-id before ‘const’
SStack.cpp:17: error: expected `)' before ‘const’
SStack.cpp:21: error: expected class-name before ‘(’ token
SStack.cpp: In member function ‘std::string&<anonymous class>::pop()’:
SStack.cpp:33: error: invalid initialization of non-const reference of type ‘std::string&’ from a temporary of type ‘const char*’
SStack.cpp: In member function ‘std::string&<anonymous class>::top() const’:
SStack.cpp:44: error: invalid initialization of non-const reference of type ‘std::string&’ from a temporary of type ‘const char*’
SStack.cpp: At global scope:
SStack.cpp:8: error: an anonymous union cannot have function members
SStack.cpp:70: error: abstract declarator ‘<anonymous class>’ used as declaration
Your include guard has the same name as your class. Remember that the preprocessor is a very simplistic search/replace feature.
#define SStack
class SStack
{
public:
// Constructor
SStack( int cap);
becomes:
#define SStack
class
{
public:
// Constructor
( int cap);
One pattern is to name it the same as your header's filename, such as STACK_H.
First of all, as was already noted, the header guard is broken.
Now, onto the actual problems:
You have misunderstood how class definition works. Your header is largely correct, what is wrong is your .cpp file. You are redefining class that you already have defined inside the header file. The proper way to provide implementation of member function is this
void SStack::SStack(const SStack& s){
DyanmicStack = new string[cap];
} or in for clearer example:
void SStack::push(const string& s){
DynamicStack[used] = s;
used++;
}.
Basically, you have to prepend the classes's name before the function name.
Also, just by copy pasting this I've noticed typo in your code (see if you can spot it ;-) ), and I would recommend rethinking the design, even if it is just an exercise.
I realized the class Pila(stack) some times ago, this is my solution:
(sorry but I'm new.. so I don't know how to indent the code here)
file: pila.h
//nodo is the type of elements that class pila contains.
struct nodo
{
int dato;
nodo* precedente;
};
class pila
{
private:
nodo* ultimo;
public:
pila();
void push(int numero);
int pop();
};
file: pila.cpp
#include <iostream>
#include"pila.h"
using namespace std;
pila::pila()
{
ultimo=NULL; // punta all'ultimo nodo inserito
}
void pila::push(int numero)
{
nodo* nuovo;
nuovo=new struct nodo;
nuovo->dato=numero;
if(ultimo==NULL)
{
nuovo->precedente=NULL;
ultimo=nuovo;
}
else
{
nuovo->precedente=ultimo;
ultimo=nuovo;
}
}
int pila::pop()
{
if (ultimo==NULL)
{
return 0;
}
else
{
int prelevato=ultimo->dato;
ultimo=ultimo->precedente;
return prelevato;
}
}
I've encountered these two error when trying to compile..
anyone knows whats wrong ?
Was thinking maybe I #include the wrong header file ?
the sample of the codes and error as per following:
Error:
Square.cpp:8: error: redefinition of ‘Square::Square(bool, Point*, std::string, int)’
Square.h:21: error: ‘Square::Square(bool, Point*, std::string, int)’ previously defined here
Square.cpp: In member function ‘Point Square::getCoord()’:
Square.cpp:22: error: expected primary-expression before ‘]’ token
Square.cpp: In member function ‘void Square::setCoord(Point*)’:
Square.cpp:32: error: expected primary-expression before ‘]’ token
Square.cpp:32: error: expected primary-expression before ‘]’ token
cpp file
#include "Square.h"`
#include <cmath>
using namespace std;
Square::Square(bool containsWarpSpace, Point coord[], string shapeName, int vertPoint):ShapeTwoD(shapeName, containsWarpSpace) {
vertPoint = vertPoint;
coord[] = coord[];
}
int Square::getVertPoint()
{
return vertPoint;
}
Point Square::getCoord()
{
return coord[];
}
void Square::setVertPoint(int verticleP)
{
vertPoint = verticleP;
}
void Square::setCoord(Point coord[])
{
coord[] = coord[];
}
header:
#include "ShapeTwoD.h"
class Square : public ShapeTwoD
{
private:
int vertPoint;
Point coord[];
public:
//Accessor
int getVertPoint();
Point getCoord();
//Mutator
void setVertPoint(int vertP);
void setCoord(Point coord[]);
//virtual member
virtual double computeArea(Point x, Point y);
Square(bool containsWarpSpace, Point coord[], std::string shapeName = "Square", int vertPoint = 4):ShapeTwoD(shapeName, containsWarpSpace){}
};
You are defining the constructor twice, once in the header and once in the implementation file. In the header, you just need to declare it like this:
Square(bool containsWarpSpace,
Point coord[],
std::string shapeName = "Square",
int vertPoint = 4);
You also need to fix the handling of coord, maybe something like changing coord to
Point* coord;
and use
Point* Square::getCoord()
{
return coord;
}
and
this->coord = coord;
in the constructor and setCoord().
Please note that your way of handling coord seems strange and dangerous to me, but without further information about what you are actually trying to do it's hard to give specific advise. Generally, consider using the standard containers over manual memory/array management.
The compiler clearly tells you the problem:
You defined the constructor twice once in header file and once in cpp file.
Also, What exactly do you intend to do with:
coord[] = coord[];
You should understand each and every statement of code that you write. Think about, What do you intend this statement to do? & then match it to the language grammar that you learnt.
Source File:
Square::Square(bool containsWarpSpace, Point coord[],
string shapeName, int vertPoint)
:ShapeTwoD(shapeName, containsWarpSpace)
{
vertPoint = vertPoint;
coord[] = coord[];
}
Header File:
Square(bool containsWarpSpace, Point coord[],
std::string shapeName = "Square", int vertPoint = 4)
:ShapeTwoD(shapeName, containsWarpSpace)
{}
Looks like two different version of the same function.
The one in the header file calls the base class constructor but does not have any code in the body of the constructor.
I have this code:
hpp:
#include <list>
using namespace std;
class funcionario
{
public:
struct Dia {
int d;
int h;
int id;
int tipo;
};
funcionario ();
void eliminar(int dia, int hora);
private:
list<Dia> agenda;
};
cpp:
#include "myClass.hpp"
funcionario::funcionario(){
agenda = list<Dia> ();
}
void funcionario::eliminar(int dia, int hora) {
list<funcionario::Dia>::iterator it;
it = agenda.begin();
while(it != agenda.end() && (*it).d <= dia) {
if((*it).d == dia && (*it).h == hora) {
agenda.erase(it);
return;
}
++it;
}
}
I get this compiling error:
Funcionario.cpp: In constructor ‘funcionario::funcionario()’:
Funcionario.cpp:5: error: cannot convert ‘std::list<funcionario::Dia, std::allocator<funcionario::Dia> >’ to ‘int’ in assignment
Funcionario.cpp: In member function ‘void funcionario::eliminar(int, int)’:
Funcionario.cpp:9: error: request for member ‘begin’ in ‘((funcionario*)this)->funcionario::agenda’, which is of non-class type ‘int’
Funcionario.cpp:10: error: request for member ‘begin’ in ‘((funcionario*)this)->funcionario::agenda’, which is of non-class type ‘int’
Funcionario.cpp:11: error: request for member ‘end’ in ‘((funcionario*)this)->funcionario::agenda’, which is of non-class type ‘int’
I don't know what I'm doing wrong.
Not sure what you're trying to achieve, but the code just needs to be fleshed out a bit with complete function definitions. I got this to compile:
#include <list>
class myClass
{
public:
myClass();
struct myStruct {
int myInfo;
};
void something();
void doSomething(myStruct & ms);
private:
std::list<myStruct> myList;
};
myClass::myClass(){
myList = list<myStruct> ();
}
void myClass::something() {
std::list<myStruct>::iterator it;
it = myList.begin();
while(it != myList.end()) {
doSomething(*it);
++it;
}
}
Incidentally (or maybe directly relevant, not sure) - the copy-initialization of myList in myClass() is unnecessary, as others have stated. The list<> default constructor will do the right thing, and more efficiently.
This seems to be working on my computer, so may it be a compiler problem? Try with another compiler and tell us if it worked
The initialization you're looking for is analogous to Initializing map and set class member variables to empty in C++? - but actually you'll get an empty list automatically (i.e. by the std::list default constructor).
--Edited to reflect your posting of the original code--
H is not declared anywhere.
and is not a valid C++ keyword or token. Use &&.
Use the local header include form of : #include "myClass.hpp"