java and c++ programs

Q:WRITE A PROGRAM TO  CALCULATE POWER OF A NUMBER
SLU:

/******************************************************************/

/* AAMIR EJAZ                                                                                                                                                          */

/*        F_43013                                                                                                                                                             */

/******************************************************************/

#include<iostream>

using namespace std;

void main()

{

int x,y;

char ch;

ab:

cout<<"enter base : ";

cin>>x;

cout<<"enter power : ";

cin>>y;

int n=1;

if(y=='0'){

            cout<<"answer is :1"<<endl;

}

else

{

while(y>0){

n=n*x;

y--;

}

cout<<"answer is"<<n<<endl;

cout<<"do you want to continue enter enter t for yes,n for no : ";

cin>>ch;

if((ch=='t')||(ch=='T'))

{

goto ab;

}

}}

Q:PROGRAM OF FILING:
SLU:

#include <iostream>

#include <fstream>

void main ()

{

char str[100];

ofstream myfile ("example.txt");

if (!myfile)

            {

            cout<<“File could not open”

            }

else

            {

            myfile << "This is a line.\n";

            myfile << "This is another line.\n";

            myfile.close();

            }

while(myfile)

            {

            myfile.getine(str,80);

            cout<<str;

            }

 }

Q:CODE OF FILING IN C+++:

SLU:

#include<iostream.h>

#include<fstream.h>

#include<conio.h>

#include<stdlib.h>

struct records

            {

            int roll_no;

            int marks;

            };

void main(void)

{

clrscr();

records rec;

char op;

int temp;

ofstream out_file("Example.dat",ios::app);

if(!out_file)

            {

            cout<<"File cannot open";

            exit(1);

            }

//////////////////////Writing to the file//////////////////

cout<<"Writing records to files";

cout<<"Enter records";

do

            {

            clrscr();

            cout<<"Enter roll no";

            cin>>rec.roll_no;

            cout<<"Enter marks";

            cin>>rec.marks;

            out_file.write((char *)&rec,sizeof(rec));

            cout<<"More records?  ";

            cin>>op;

            }while(op=='y');

out_file.close();

///////////////////Reading all records from file///////////////////

ifstream in_file("Example.dat");

clrscr();

long int num=1;

if(!in_file)

            {

            cout<<"Cannot open file";

            exit(1);

            }

while(in_file.read((char *)&rec,sizeof(rec)))

            {

            cout<<"\nRecord Number:"<<num;

            cout<<"\nRoll No:  "<<rec.roll_no;

            cout<<"\nMarks:  "<<rec.marks;

            num++;

            }

in_file.close();

getche();

//////////////Finding a record from the file /////////////////

clrscr();

ifstream find("Example.dat");

if(!find)

            {

            cout<<"Cannot open file";

            exit(1);

            }

cout<<"\nEnter the roll number you want to find";

cin>>temp;

num=1;

int found=0;

while(find.read((char *)&rec,sizeof(rec)))

            {

            if(rec.roll_no==temp)

                        {

                        find.seekg((num)*sizeof(rec));

                        cout<<"YOUR RECORD IS";

                        cout<<"\nRoll No:  "<<rec.roll_no;

                        cout<<"\nMarks:  "<<rec.marks;

                        found=1;

                        }

            num++;

            }

if(found==0)

            cout<<"The record could not be found";

getche();

find.close();

//////////////Updating a record in the file /////////////////

clrscr();

fstream update("Example.dat",ios::in|ios::out);

if(!update)

            {

            cout<<"Cannot open file";

            exit(1);

            }

cout<<"\nEnter the roll number whose marks you want to update";

cin>>temp;

num=0;

found=0;

long int pos;

while(update.read((char *)&rec,sizeof(rec)))

            {

            if(rec.roll_no==temp)

                        {

                        cout<<"YOUR RECORD IS";

                        cout<<"\nRoll No:  "<<rec.roll_no;

                        cout<<"\nMarks:  "<<rec.marks;

                        cout<<"\nEnter new marks";

                        cin>>rec.marks;

                        pos=update.tellp();

                        update.seekp(pos-sizeof(rec));

                        update.write((char*)&rec,sizeof(rec));

                        update.close();

                        found=1;

                        }

            num++;

            }

if(found==0)

            cout<<"The record could not be found";

            getche();

}