Pointers and void pointer and precedence of & and * operators in pointers.

Pointers
Definition:- A pointer is a variable that stores the memory address of another another variable.

void pointer :-( it can contain address of any data type )
syntax:-    void *pointer_name;
example:- void *v_ptr;
A void pointer does not have any data-type associated it with and can contain the address of any type of variable.
example:- void v_ptr;
                char ch;
                 int i;
                 float fvar;
                 v_ptr= &ch;
                 v_ptr= &i;
                 v_ptr =&fvar;

Precedence of & and * operator:-
Both are unary operators and have precedence equal to other unary operators.
Their associativity is from right to left.
example:-   int n=10,++*ptr;
                  ptr = &n;
                  ptr = 1024
                 
                   ++ *ptr =  ++(1024)
                                = ++(10)
                                = 11
  
                   *ptr++  = (*1024)++
                                =10 ++
                                =10

                    * ++ptr = *(++1024)
                                 = *(1026)
                                 = data at 1026

Program of magic. magic.cpp

#include<iostream.h>
#include<conio.h>
int main()
{
   
    int i,ans=0;
    clrscr();
    cout<<"\nChoose one number in your mind from 1 to 63 \n";
    cout<<"\n1    3    5    7    9    11    13    15 \n";
    cout<<"\n17    19    21    23    25    27    29    31 \n";
    cout<<"\n33    35    37    39    41    43    45    47 \n";
    cout<<"\n49    51    53    55    57    59    61    63 \n";
    cout<<"Write 0 if number in your mind is present or else write 1 if not present\n";
    cin>>i;
    if(i==0)
    {
        ans=ans+1;
    }
    else
    {
        ans=ans;
    }


    cout<<"\n2    3    6    7    10    11    14    15 \n";
    cout<<"\n18    19    22    23    26    27    30    31 \n";
    cout<<"\n34    35    38    39    42    43    46    47 \n";
    cout<<"\n50    51    54    55    58    60    62    63 \n";
    cout<<"Write 0 if number in your mind is present or else write 1 if not present\n";
    cin>>i;
    if(i==0)
    {
        ans=ans+2;
    }
    else
    {ans=ans;}

    cout<<"\n4    5    6    7    12    13    14    15 \n";
    cout<<"\n20    21    22    23    28    29    30    31 \n";
    cout<<"\n36    37    38    39    44    45    46    47 \n";
    cout<<"\n52    53    54    55    60    61    62    63 \n";
    cout<<"Write 0 if number in your mind is present or else write 1 if not present\n";
    cin>>i;
    if(i==0)
    {
        ans=ans+4;
    }else
    {ans=ans;}
    cout<<"\n8    9    10    11    12    13    14    15 \n";
    cout<<"\n24    25    26    27    28    29    30    31 \n";
    cout<<"\n40    41    42    43    44    45    46    47 \n";
    cout<<"\n56    57    58    59    60    61    62    63 \n";
    cout<<"Write 0 if number in your mind is present or else write 1 if not present\n";
    cin>>i;
    if(i==0)
    {
        ans=ans+8;
    }else
    {ans=ans;}
    cout<<"\n16    17    18    19    20    21    22    23 \n";
    cout<<"\n24    25    26    27    28    29    30    31 \n";
    cout<<"\n48    49    50    51    52    53    54    55 \n";
    cout<<"\n56    57    58    59    60    61    62    63 \n";
    cout<<"Write 0 if number in your mind is present or else write 1 if not present\n";
    cin>>i;
    if(i==0)
    {
        ans=ans+16;
    }else
    {ans=ans;}

    cout<<"\n32    33    34    35    36    37    38    39 \n";
    cout<<"\n40    41    42    43    44    45    46    47 \n";
    cout<<"\n48    49    50    51    52    53    54    55 \n";
    cout<<"\n56    57    58    59    60    61    62    63 \n";
    cout<<"Write 0 if number in your mind is present or else write 1 if not present\n";
    cin>>i;
    if(i==0)
    {
        ans=ans+32;
    }else
    {ans=ans;}
    cout<<"The answer in your mind is : ";
    cout<<ans;
    getch();
    return 0;
}

Program to find GCD of two numbers

#include<iostream.h>
int main()
{
int first_number,second_number,gcd,i;
cout<<"Enter First Number : ";
cin>>first_number;

cout<<"Enter Second Number: ";
cin>>second_number;

for(i=1;i<=first_number&&i<=second_number;i++)
{

     if(first_number%i==0 && second_number%i == 0 )
{
                     gcd=i;

    }

}

cout<<"Greatest Common Division (GCD):"<<gcd<<endl;
return 0;
}

******Output******

Enter First Number: 9

Enter Second Number: 24

Greatest Common Division (GCD):3 

What is GCD of two numbers?
 It means a greatest number which divides both numbers
For example: Two numbers are 9 and 24
Numbers which divides both are 1 and 3 in which greatest number is 3
So 3 is the GCD of 9 and 24

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Program in C++ to count heart beats of a person by its age from born

# include <iostream.h>
int main()
{
int age,heartbeats;
cout<<"Enter Age: ";
cin>>age;
cout<<"Enter Number of Heartbeats per min: ";
cin>>heartbeats;

heartbeats = heartbeats * 60; //heartbeats per hour

heartbeats = heartbeats * 24; //heartbeats per day

heartbeats = heartbeats * 365; //heartbeats per year

cout<<"Your Heart has beat "<<heartbeats * age<<" times since you were born."<<endl;

return 0;
}

-----------------------OUTPUT---------------------

 Enter Age: 26

 Enter Number of Heartbeats per min: 70

 Your Heart has beat  956592000  times since you were born.

Program in C++ for Fibonacci Series using recursion function

#include<iostream.h>
fibonacci(int);            //function prototype
void main()
{
int n,i,f;
cout<<"Enter the total elements in the series : ";
cin>>n;
cout<<"\nThe Fibonacci series is:\n";
for(i=0;i<n;i++)
    {
        f=fibonacci(i); //function call
        cout<<f<<"  ";
    }
}

fibonacci(int n)        //function definition
{
    int f;
    if(n==0)
    return 0;
    else if(n==1)
    return 1;
    else
    f=fibonacci(n-1)+fibonacci(n-2);  /*Two recursion function calling itself with different arguments.*/
    return f;
}

-----------------OUTPUT---------------

Enter the total elements in the series :  7

The Fibonacci series is:

0    1    1    2    3    5    8

Note: -When a function call itself within its body is known as recursion function .The function calling has different arguments.

Fibonacci Series means addition of previous two numbers example 0+1=1 , 1+1=2 , 1+2=3 ,2+3=5 , 3+5 =8 , and so on .So the Fibonacci Series is 0,1,1,2,3,5,8,13,21,34

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Using power function display armstrong number

#include<iostream.h>
#include<math.h>
int main()
{
int sum,n,temp,rem;
cout<<"The Armstrong number between the range 1 to 500 are : \n"; 
for(int x=1;x<=500;x++)
{
n=x;
sum=0;
temp=n;
do
{
rem=n%10;
n=n/10;
int p;
p=pow(rem,3);
sum=sum+p;
}while(n!=0);
if(sum==temp)
cout<<x<<"\t";
}
cout<<"\t";
return 0;
}

Output:
The Armstrong number between the range 1 to 500 are : 
1      153     370     371     407
 

Program to dispaly armstrong number between 1 to 500

#include<iostream.h>
int main()
{
int sum,n,temp,rem;
cout<<"The Armstrong number between the range 1 to 500 are : \n"; 
for(int x=1;x<=500;x++)
{
n=x;
sum=0;
temp=n;
do
{
rem=n%10;
n=n/10;
sum=sum+rem*rem*rem;
}while(n!=0);
if(sum==temp)
cout<<x<<"\t";
}
cout<<"\t";
return 0;
}

Output:

 The Armstrong number between the range 1 to 500 are :
1        153         370       371        407

C++ Program to check whether number is Armstrong number

#include<iostream.h>
int main()
{
      int sum,temp,rem,n;
     cout<<"Enter the number \n";
     cin>>n;
     cout<<" Entered number is \t";
     cout<<n;
     cout<<"\n";
     sum=0; 
     temp=n;
      do
        {
                rem=n%10;
                n=n/10;
                sum=sum+rem*rem*rem;
           }while(n!=0);
     if(sum==temp)
            cout<<"This is Armstrong number.\n";
   else
           cout<<"This is not Armstrong number.\n";
return 0;
}

Output:-

Enter the number

371

Entered number is    371

This is Armstrong number.

Microcontroller

Comparison between micro-controller and microprocessor

Sr No.	Microcontroller	Microprocessor
1.	Inbuilt RAM or ROM	Do not have inbuilt RAM or ROM
2.	Inbuilt Timer	Do not have inbuilt Timer
3.	I/O ports are available	I/o ports are not available ,requires extra device like 8155 or 8255.
4.	Inbuilt serial port	Do not have inbuilt serial port , requires extra devices like 8250 or 8251
5.	Separate memory to store program and data	Program and data are stored in same memory
6.	Few instructions to read or write data to or from external memory.	Many instructions to read or write data from or to external memory.

A microcontroller is an entire computer manufactured on a single chip. Microcontrollers are usually dedicated  devices embeded within an application
Example microcontrollers are used as engine controllers in engine automobiles and as exposure and focus controllers in cameras .

Features of 8051:-

• 8 bit bus and 8 bit ALU.
• 16 bit address bus  -64 KB of RAM and ROM.
• On-chip RAM 128(256 ) bytes (Data Memory) and On Chip ROM -4 KB (Program memory)
• Four 8 -bit bi directional input /output ports.
• Programmable serial ports i.e. One UART(serial port).
• Power saving mode.
• All modern versions are CMOS.

Computer Questions

Computer Questions

1.When data and acknowledgement are sent in the same frame ,this is called as
A) Piggy packing
B) Piggy backing
C) Back packing
D) Good packing

Answer:-B) Piggy backing

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2.Encryption and Decryption is the responsibility of ________Layer.
A) Physical
B) Network
C) Application
D) Datalink 

Answer:- C) Application

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3.An analog signal carries 4 bits in each signal unit .If 1000 signal units are sent per second ,then baud rate and bit rate of the signal are ____ and ____.
A) 4000 bauds \ sec & 1000 bps
B) 2000 bauds \ sec & 1000 bps
C) 1000 bauds \ sec & 500 bps
D) 1000 bauds \ sec & 4000 bps

Answer:- D) 1000 bauds \ sec & 4000 bps

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4.The VLF and LF bauds use ______ propagation for communication.
A) Ground
B) Sky
C) Line of sight
D) Space

Answer:- A) Ground

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5) Using the RSA public key crypto system ,if p=13 q=31 and d=7,then the value of e is
A) 101
B) 103
C) 105
D) 107

Answer:- 105

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6)FAN IN of a component A is defined as
A) Number of components that can call or pass control to component A
B) Number of components that are called by component A.
C) Number of components related to component A.
D) Number of components dependent on component A.

Answer:-A) Number of components that can call or pass control to component A

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7) The relationship of data elements in a module is called
A) Coupling
B)  Modularity
C) Cohesion
D) Granularity

Answer:- C) Cohesion

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8)Software Configuration Management is the discipline for systematically controlling
A) the changes due to the evolution of work products as the project proceeds.
B) the changes due to defects (bugs) being found and then fixed
C)the changes due to requirement changes
D) all the above

Answer:- D) all the above

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9) Which one the following is not a step of requirement engineering?
A) Requirement elicitation
B) Requirement analysis
C) Requirement design
D) Requirement documentation

Answer:- C) Requirement design

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10)Testing of software with actual data and in actual environment is called
A) Alpha testing
B) Beta testing
C) Regression testing
D) None of the above

Answer:- B) Beta testing

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11) The student marks should not be greater than 100 .This is
A) Integrity constraint
B) Referential constraint
C) Over-defined constraint
D) Feasible constraint

Answer:- A) Integrity constraint

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12) Which of the following operators can not be overloaded in C++?
A) *
B) +=
C) ==
D) ::

Answer :- D) ::

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