Problem in connecting QRadioButton to QTabWidget tab

[cneha]

I am creating an application in which i want a functionality in which whenever a radio button is checked,the content appearing in a tab must be changed.but the problem is when i connect the button with the tab,nothing happens.I am creating an object of a class which creates the tab firstly, within the slot to change the content of the tab whenever it will be checked. But this is not working as the content of tab is not changing.
Can any one help with this problem?
I am attaching the code of my program as well.
Header file:


#ifndef V_LAB_H
#define V_LAB_H
#include<QDialog>
#include<QVBoxLayout>
#include<QHBoxLayout>
#include<QGroupBox>
#include<QRadioButton>
#include<QPalette>
#include<QSize>
#include<QTabWidget>
#include<QLabel>
class QVBoxLayout;
class QGroupBox;
class QRadioButton;
class QPalette;
class QSize;
class QPushButton;

class QTabWidget;

/*class psudo_code:public QWidget
{
Q_OBJECT
public:
psudo_code(QWidget *parent = 0);
private:
QLabel *label1;
QVBoxLayout *main_layout1;
};*/

class v_lab:public QDialog
{
Q_OBJECT
public:
v_lab(QWidget *parent = 0);
signals:




public slots:
void peeyush();


private:

QPalette *p;
QGroupBox *maingroup;
QGroupBox *box;
QHBoxLayout *mainlayout;

QVBoxLayout *main_left_pane_layout;
QVBoxLayout *left_pane_box;
QVBoxLayout *left_pane_box1;
QVBoxLayout *left_pane_box2;
QVBoxLayout *left_pane_box3;
QGroupBox *box1;

QGroupBox *box2;

QGroupBox *box3;

QRadioButton *linear_search;
QRadioButton *binary_search;
QRadioButton *bubble_sort;
QRadioButton *selection_sort;
QRadioButton *infix_traversal;
QRadioButton *prefix_traversal;
QRadioButton *postfix_traversal;
QRadioButton *bfs;
QRadioButton *dfs;
QRadioButton *shortest_path;
QTabWidget *tab;


QString string2;
};


class algorithm:public QWidget
{
Q_OBJECT
public:
algorithm(const QString &string,QWidget *parent = 0);



private:
QLabel *label;
QLabel *label1;
QVBoxLayout *main_layout;
QVBoxLayout *main_layout1;
};

#endif // V_LAB_H

source file (v_lab.cpp)


#include<QtGui>
#include "v_lab.h"

v_lab::v_lab(QWidget *parent)
:QDialog(parent)
{

setWindowTitle("Virtual Lab");
maingroup=new QGroupBox(this);
maingroup->setTitle("Algorithms");
maingroup->setMinimumWidth(200);
maingroup->setMaximumWidth(240);
maingroup->setFlat(false);
p=new QPalette;
p->setColor(QPalette::Background,QColor(233,212,102)) ;
setPalette(*p);


box=new QGroupBox(maingroup);
box->setFlat(false);
box->setTitle("Searching Algorithm");




linear_search=new QRadioButton("Linear Search",box);
linear_search->setChecked(1);
binary_search=new QRadioButton("Binary Search",box);


box1=new QGroupBox(maingroup);
box1->setFlat(false);
box1->setTitle("Sorting Algorithms");


bubble_sort=new QRadioButton("Bubble Sort",box1);
selection_sort=new QRadioButton("Selection Sort",box1);


box2=new QGroupBox(maingroup);
box2->setFlat(false);
box2->setTitle("Tree Algorithms");


infix_traversal=new QRadioButton("Infix Traversal",box2);
prefix_traversal=new QRadioButton("Prefix Traversal",box2);
postfix_traversal=new QRadioButton("Postfix Traversal",box2);



box3=new QGroupBox(maingroup);
box3->setFlat(false);
box3->setTitle("Graph Algorithms");


bfs=new QRadioButton("BFS",box3);

dfs=new QRadioButton("DFS",box3);
shortest_path=new QRadioButton("Shortest Path",box3);

QString string1="Start Tab";
tab=new QTabWidget;
tab->addTab(new algorithm(string1),"Algorithm");
//tab->addTab(new psudo_code(),"Pseduo-Code");
tab->setMinimumWidth(250);
tab->setMaximumWidth(400);




//Layout
mainlayout=new QHBoxLayout(this);
mainlayout->addWidget(maingroup);

mainlayout->addWidget(tab);
mainlayout->addStretch();
main_left_pane_layout=new QVBoxLayout(maingroup);

main_left_pane_layout->addWidget(box);
main_left_pane_layout->addWidget(box1);
main_left_pane_layout->addWidget(box2);
main_left_pane_layout->addWidget(box3);

left_pane_box=new QVBoxLayout(box);

left_pane_box->addWidget(linear_search);
left_pane_box->addWidget(binary_search);


left_pane_box1=new QVBoxLayout(box1);

left_pane_box1->addWidget(bubble_sort);
left_pane_box1->addWidget(selection_sort);

left_pane_box2=new QVBoxLayout(box2);

left_pane_box2->addWidget(infix_traversal);
left_pane_box2->addWidget(prefix_traversal);
left_pane_box2->addWidget(postfix_traversal);

left_pane_box3=new QVBoxLayout(box3);

left_pane_box3->addWidget(bfs);
left_pane_box3->addWidget(dfs);
left_pane_box3->addWidget(shortest_path);


connect(binary_search,SIGNAL(clicked()),this,SLOT( peeyush()));

}
algorithm::algorithm(const QString &string,QWidget *parent)
:QWidget(parent)
{

label=new QLabel(string);
main_layout=new QVBoxLayout;
main_layout->addWidget(label);
main_layout->addStretch();
setLayout(main_layout);
}

void v_lab::peeyush()
{
string2="test 2";
new algorithm(string2);

//exit(1);
}

main.cpp


#include <QApplication>
#include"v_lab.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
v_lab *dialog = new v_lab;


dialog->show();
return app.exec();
}