C++ PROGRAMMING

3 Three Nested For Loops - Very Gainful C++ Learning

Three nested for loops in cplusplus programming language to evaluate loop learning and nested loop learning methods.

#include <iostream>
using namespace std;
void main ()
{
for (int i=1;i<=3;i++)
{
for(int j=1;j<=3;j++)
{
for(int k=1;k<=3;k++)
{
cout<<i<<j<<k<<",";
}
}
}
}

BUBBLE SORTING by making class and functions

Bubble sorting by making class and functions

Bubble sorting useful technique to sort array. Make a class and some related functions and then bubble sorting ..

#include<iostream>

using namespace std;
const int size = 10;
class array
{
private:
int a[size];
int n;
public:
array()
{
for ( int i=0; i<size; i++ )
{
a[i];
n = 0;
}
}
void read()
{
int num;
cout<<"how many values you want to insert ?? "<<endl;
cin>>num;
for ( int i = 0; i<num; i++)
{
cout<<"Enter value: "<<endl;
cin>>a[ i ];
}
n = num;

}
void display ()
{
for (int i = 0; i<n; i++ )
cout<<a[ i]<<endl;
}

void sort()
{
for(int i = 0; i<n-1; i++)
for(int j = 0; j<n-i-1;j++)
if(a[ j+1]<a[ j ] )
{
int temp = a[ j ];
a[j] = a[ j+1 ];
a[ j+1 ] = temp;
}
}
};

void main( )
{
array arr;
arr.read( );
cout<<"The entered values are: "<<endl;
arr.display( );
arr.sort( );
cout<<"arrays values after sorting"<<endl;
arr.display( );

BUBBLE SORTING for character array in c++

Bubble sorting for character array

Bubble sorting is easy way to sort (arrange ) an array. which is either for character or for integers.

#include <iostream>

using namespace std;

void main ()

{

const char size=50;

char a[size]= {'a','v','x','d','s','e','f','e','s','e','g','e','d','y','s','w','g','a','f','b','d','b','c','x','c'};

cout<<"The unsorted array is";

for(int i=0;i<size-1;i++)

cout<<a[i]<<",";

cout<<"\n sorted array is"<<endl;

for(i=0;i<size-1;i++)

{

for(int j=0;j<size-i-1;j++)

if(a[j]>a[j+1])

{

int temp=a[j];

a[j]=a[j+1];

a[j+1]=temp;

}

cout<<a[j]<<",";

}

LINEAR SEARCH for an array in c++

Linear search for an array

Linear search is used to search out the required number from a very large array of elements

#include <iostream>

using namespace std;

void main ()

{

const int size=5;

int a[size]={4,5,6,7,7};

int n;

cout<<"enter the no which you want to search:";

cin>>n;

bool found=false;

for(int i=0;i<size&&!found;i++)

if(a[i]==n)

found=true;

if(found ==true)

cout<<"Number:"<<n<< "is found at location:"<<i<<endl;

else

cout<<"Number is NOT found";

}

LINEAR SEARCH by making functions and class

Linear search by making class and functions

Linear search which is good for small data. Make a class array and some functions to make linear search easiy.

#include<iostream.h>
const int size = 10;
class array
{
private:
int a[size];
int n;
public:
array()
{
for ( int i=0; i<size; i++ )
{
a[i];
n = 0;
}
}
void read()
{
int num;
cout<<"how many values you want to insert ?? "<<endl;
cin>>num;
for ( int i = 0; i<num; i++)
{
cout<<"Enter value: "<<endl;
cin>>a[i];
}
n = num;

}
void display ()
{
for (int i = 0; i<n; i++ )
cout<<a[i]<<endl;
}
void search()
{
bool Found = false;
int key;
cout<<"enter key: "<<endl;
cin>>key;

for(int i= 0; i<n && !Found; i++)
if (key == a[i])
if(Found)
{
bool Found = true;
}
if(Found)
{
cout<<"found"<<endl;
}

else
{
cout<<"not found"<<endl;
}
}

};
void main()
{
array arr;
arr.read();
cout<<"The entered values are: "<<endl;
arr.display();
arr.search();
}

BINARY SEARCH by making functions and class in c++

Binary search by making class and functions

Binary search is faster and useful. you have to make a class and some related functions and take a binary search ..

#include<iostream>
using namespace std;
const int size = 10;
class array
{
private:
int a[size];
int n;
public:
array()
{
for (int i = 0; i<size; i++)
a[i] = 0;
n = 0;
}

void read()
{
int num;
cout<<"how many values you want to enter ?"<<endl;
cin>>num;
for(int i = 0; i<num; i++)
{
cout<<"Enter value:"<<endl;
cin>>a[i];
}
n = num;

}

void display()
{
for (int i = 0; i<n; i++)
cout<<a[i];
cout<<endl;
}

void search()
{
bool found = false;
int low = 0;
int high = n-1;
int key;
cout<<"enter key:"<<endl;
cin>>key;
while(low <= high && !found)
{
int mid = (low + high)/2;

if (key == a[mid])
found = true;
else if(key<a[mid])
high = mid - 1;
else
low = mid + 1;
}

if(found == true)
cout<<"Found"<<endl;
else
cout<<"not found"<<endl;
}

};

void main()
{
array arr1, arr2;
arr1.read();
cout<<"the entered array is : "<<endl;
arr1.display();
arr1.search();
}

MERGING TWO ARRAYS in c++

Merging two arrays

First take two arrays sort them and merge them into third array.

·
#include <iostream.h>
const int SIZE = 10;
class Array
{
private:
int a[SIZE];
int n;
public:
Array()
{
for (int i=0;i<SIZE;i++)
a[i] = 0;
n = 0;
}
void read()
{
int num;
cout<<"how many values you want to enter ? "<<endl;
cin>>num;
for(int i = 0; i<num; i++)
{
cout<<"enter values: "<<endl;
cin>>a[i];
}
n = num;
}
void display()
{
for (int i=0;i<n;i++)
cout << a[i];
cout << endl;
}
void merge(Array a1, Array a2)
{
int i=0,j=0;
while (i< a1.n && j< a2.n )
{
if (a1.a[i] < a2.a[j])
{
a[n] = a1.a[i];
i++;
}
else
{
a[n] = a2.a[j];
j++;
}
n++;

}
while (i < a1.n)
{
a[n] = a1.a[i];
i++; n++;
}
while (j < a2.n)
{
a[n] = a2.a[j];
j++; n++;
}
}
};
void main()
{
Array itm, a2, a3;
itm.read();
itm.display();
cout<<"for 2nd array ";
a2.read();
a2.display();

a3.merge(itm,a2);
a3.display();

}

BINARY SEARCH in c++

Binary search

Binary search is useful for large data. It is faster than linear search but complex.Here an example of linear search...

#include <iostream>

using namespace std;

const int size=6;

void main ()

{

int a[size]={4,5,6,7,7,8};

int n;

cout<<"enter the no which you want to search:";

cin>>n;

bool found=false;

int low=0,high=size-1;

int mid=(low+high+1)/2;

while(low<=high&&!found){

if(a[mid]==n)

found=true;

else if(a[mid]>n)

high=mid-1;

else

low=mid+1;

mid=(low+high+1)/2;

}

if(found==true)

cout<<"NO:"<<n<< "is found at location:"<<mid<<endl;

else

cout<<"NOT found";

}

STATIC DATA MEMBERS & CONSTANT MEMBER FUNCTIOS in C++

STATIC DATA MEMBERS & CONSTANT MEMBER FUNCTIONS

Static data members

static data member is a data member that is shared by all the objects of a class.Only one copy of static data member is kept in memory

By this example your idea will be clear about static data members

static data members

#include <iostream>

using namespace std;

class alpha

{

private:

int id;

static int count;

public:

alpha()

{

count++;

id=count;

}

void print()

{

cout<<"My id is"<<id;

cout<<"count is"<<count;

}

};

int alpha ::count=0; //definition of count

void main ()

{

alpha a1,a2,a3;

a1.print();

a2.print();

a3.print();

}

This example will clear your idea . This simple ,easy and awesome space for beginners

....................................................................................................................................................................................

Constant data members

If you dont want to change data members then keyword const is used.

This example demonstrates const member functions

class aclass

{

private:

int alpha;

public:

void nonFunc() // non const member function

{

alpha=100; //ok

}

void conFunc() const // constant member function

{

alpha=100; // error , cannot modify a member

}

};

This example surely help you in understanding of const member function

This is a completely solved example.

#include <iostream>

using namespace std;

class rational

{

private:

int num;

int dnum;

public:

rational():num(1),dnum(1)

{}

void get ()

{

cout<<"enter numerator";

cin>>num;

cout<<"enter denomenator";

cin>>dnum;

}

void print () const // const keyword is used

{

cout<<num<<"/"<<dnum<<endl;

}

void multi(rational r1,rational r2)

{

num=r1.num*r2.num;

dnum=r1.dnum*r2.dnum;

}

};

void main ()

{

rational r1,r2,r3;

r1.get();

r2.get();

r3.multi(r1,r2);

r3.print();

}

For practice you should solve one more programming example like distance class. Practice makes a man perfect

POINTERS in C++

Pointers

A variable that holds an address value is called a pointer variable or simply pointer.Pointers are hobgoblin of c++ programming.

What are pointers for ? Here some common uses are

· Accessing array elements.

· Passing arguments to a function when the function needs to modify the origonal argument.

· Passing arrays and strings to function.

· Obtaining memory from the system.

· Creating data structures such as linked lists.

Pointers are important feature of c++ programming. But many other languages such as java , visual Basics have no pointers. You can do a lot of programming without pointers but pointers are assentials for c++ programming language.

The idea behind pointers is not complicated.Every byte in computer memory has an address.Addresses are numbers,just as for houses on a street.

The address of operator &:

Address occupied by a variable using the address operator &. Here is a short example that will help you in understanding that topic.

#include <iostream>

using namespace std;

int main ( )

{

int var1 = 10;

int var2 = 20;

cout << &var1<<endl;

cout << &var2<<endl;

return 0;

}

Run this program on your system and machine and then see what the address of var1 and var2 .

Address is not the value of var1 which is 10. Address would be in the form of 6to7 digits.

Address by pointer variables:

By the address we can find where things in memory.

What is the data type of pointer variable ?

A pointer to int ,is not type int .You might think a pointer data type would be called something like pointer or p or ptr.

Example of pointer ( address variables )

#include <iostream>

using namespace std;

int main ( )

{

int var1 = 10;

int var2 = 20;

cout << &var1<<endl;

cout << &var2<<endl;

int *ptr ;

ptr = &var1 ;

cout <<ptr ;

ptr = &var2 ;

cout<< ptr;

return 0;

}

Sample run can be shown when you run this program on your system.

Pointers must have a value:

An address like 0*8ffff4ff can be thought of as a pointer constant.

When we first define a variable , it holds no value. It may hold a garbage value.But in case of pointers , a garbage value is the address of something in memory. So before a pointer is used , a specific address must be placed in it.

ptr = &var;

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