cell.h No relevant classes found. No output generated

[rahulvishwakarma]

Hi to all, I've centos6.4 in VM AND Qt5.2.1 I am building a project given in book "C++-GUI-Programming-with-Qt-4-1st-ed.pdf". but in book it is by coding and i am building by using GUI.
here is my cell.h file :-

#ifndef CELL_H
#define CELL_H

#include <QTableWidgetItem>
#include <QWidget>

class Cell : public QTableWidgetItem
{

public:
Cell();

QTableWidgetItem *clone() const;
void setData(int role, const QVariant &value);
QVariant data(int role) const;
void setFormula(const QString &formula);
QString formula() const;
void setDirty();

private:
QVariant value() const;
QVariant evalExpression(const QString &str, int &pos) const;
QVariant evalTerm(const QString &str, int &pos) const;
QVariant evalFactor(const QString &str, int &pos) const;

mutable QVariant cachedValue;
mutable bool cacheIsDirty;
};

and here is its cell.cpp file :-


#include "cell.h"
#include <QtWidgets>

Cell::Cell()
{
setDirty();
}

QTableWidgetItem *Cell::clone() const
{
return new Cell(*this);
}

void Cell::setData(int role, const QVariant &value)
{
QTableWidgetItem::setData(role, value);
if(role == Qt::EditRole)
{
setDirty();
}
}

QString Cell::formula() const
{
return data(Qt::EditRole).toString();
}

const QVariant Invalid;

QVariant Cell::data(int role) const
{
if(role == Qt::DisplayRole)
{
if(this->value().isValid())
return value().toString();
else
return "####";
}
else if(role == Qt::TextAlignmentRole)
{
if(this->value().type() == QVariant::String)
return int(Qt::AlignCenter| Qt::AlignVCenter);
else
return int(Qt::AlignRight | Qt::AlignVCenter);
}
else
{
return QTableWidgetItem::data(role);
}
}

void Cell::setFormula(const QString &formula)
{
setData(Qt::EditRole, formula);
}

void Cell::setDirty()
{
this->cacheIsDirty = true;
}

QVariant Cell::value() const
{
if (cacheIsDirty)
{
cacheIsDirty = false;

QString formulaStr = formula();
if (formulaStr.startsWith('\''))
{
cachedValue = formulaStr.mid(1);
}
else if (formulaStr.startsWith('='))
{
cachedValue = Invalid;
QString expr = formulaStr.mid(1);
expr.replace(" ", "");
expr.append(QChar::Null);

int pos = 0;
cachedValue = evalExpression(expr, pos);
if (expr[pos] != QChar::Null)
cachedValue = Invalid;
}
else
{
bool ok;
double d = formulaStr.toDouble(&ok);
if (ok)
{
cachedValue = d;
}
else
{
cachedValue = formulaStr;
}
}
}
return cachedValue;
}

QVariant Cell::evalExpression(const QString &str, int &pos) const
{
QVariant result = evalTerm(str, pos);
while (str[pos] != QChar::Null)
{
QChar op = str[pos];
if (op != '+' && op != '-')
return result;
++pos;

QVariant term = evalTerm(str, pos);
if (result.type() == QVariant::Double
&& term.type() == QVariant::Double)
{
if (op == '+')
{
result = result.toDouble() + term.toDouble();
}
else
{
result = result.toDouble() - term.toDouble();
}
}
else
{
result = Invalid;
}
}
return result;
}

QVariant Cell::evalTerm(const QString &str, int &pos) const
{
QVariant result = evalFactor(str, pos);
while (str[pos] != QChar::Null)
{
QChar op = str[pos];
if (op != '*' && op != '/')
return result;
++pos;

QVariant factor = evalFactor(str, pos);
if (result.type() == QVariant::Double
&& factor.type() == QVariant::Double)
{
if (op == '*')
{
result = result.toDouble() * factor.toDouble();
}
else
{
if (factor.toDouble() == 0.0)
{
result = Invalid;
}
else
{
result = result.toDouble() / factor.toDouble();
}
}
}
else
{
result = Invalid;
}
}
return result;
}


QVariant Cell::evalFactor(const QString &str, int &pos) const
{
QVariant result;
bool negative = false;

if (str[pos] == '-')
{
negative = true;
++pos;
}

if (str[pos] == '(')
{
++pos;
result = evalExpression(str, pos);
if (str[pos] != ')')
result = Invalid;
++pos;
}
else
{
QRegExp regExp("[A-Za-z][1-9][0-9]{0,2}");
QString token;

while (str[pos].isLetterOrNumber() || str[pos] == '.')
{
token += str[pos];
++pos;
}

if (regExp.exactMatch(token))
{
int column = token[0].toUpper().unicode() - 'A';
int row = token.mid(1).toInt() - 1;

Cell *c = static_cast<Cell *>(
tableWidget()->item(row, column));
if (c)
{
result = c->value();
}
else
{
result = 0.0;
}
}
else
{
bool ok;
result = token.toDouble(&ok);
if (!ok)
result = Invalid;
}
}

if (negative)
{
if (result.type() == QVariant::Double)
{
result = -result.toDouble();
}
else
{
result = Invalid;
}
}
return result;
}

output is :- 13196
and output should be :- 13197

of course i have not implemented toolbar but remaining should work.
how to remove error :-
No relevant classes found. No output generated

[anda_skoa]

This is not an error, just an information.

MOC read the cell.h file and didn't find any Q_OBJECT or Q_GADGET class in it, so it didn't have to do anything.

A re-run of qmake will likely get rid of that.

Cheers,
_

[rahulvishwakarma]

i ran qmake the error ( or information ) gone but question is still there, how to build output like book's output using Qt 5.2.
currently i want to set vertical header items form 0 to 999. tried some some googling, found like this :-


for(int i = 0; i < RowCount; i++)
{
QTableWidgetItem *item = new QTableWidgetItem;
item->setText(QString::number(i));
this->setVerticalHeaderItem(i,item);
}

but it doesn't works.

[anda_skoa]

Well, you code is just the table cell class, there is no code to add data to the table widget.

Your first screenshot shows an empty table, your second shows one that has actual rows and columns.

Either add cell items or call setRowCount() and setColumnCount()

Cheers,
_