/*
Multiplication Table (10 * 10)
*/
#include <iostream>

using namespace std;

int main(void)
{
 int x,y;
 char waitInput;

 for(x=1; x<=10; x++)
 {
  for(y=1; y<=10; y++)
  {
   //use horizontal tab (\t) to align properly
   cout << "\t" << (x*y);
  }

  //newlines
  cout<<endl<<endl;
 }

 cin>>waitInput;
 return 0;
}

/*
Reverse the number
*/
#include <iostream>

using namespace std;

int main(void)
{
 long number, remainder, reverseNumber = 0;
 char hang;

 cout<< "Enter the number: ";
 cin>>number;
 
 while(number)
 {
  //extract the last digit from the number
  remainder = number % 10;  

  //build the reverseNumber digit by digit
  reverseNumber = (reverseNumber * 10) + remainder;

  //exclude the last digit from the number
  //ready for the next evaluation
  number = number / 10;    
 }

 cout<< "Reversed number = " << reverseNumber <<endl;
 
 //to let console stay
 cin>>hang;
 
 return 0;
}

//Sample 1

Enter the number: 1235
Reversed number = 5321

//Sample 2

Enter the number: 1023
Reversed number = 3201

//Sample 3

Enter the number: 5007
Reversed number = 7005

//*Sample 4

Enter the number: 012
Reversed number = 21

//*Sample 5

Enter the number: 210
Reversed number = 12

Write a C++ program which checks if a number is a prime number or not?

1 and 5 (the number itself) can evenly divide 5 so they are factors of 5.
2, 3, 4 are cannot evenly divide 5 so they are not factors of 5.
Therefore, 5 is a Prime Number.

/*
Perfect Numbers
show perfect numbers from 1-1000
*/

#include <iostream>

using namespace std;

int main(void)
{ 
 //variables
 int i,j,sumOfFactors;

 cout << "These are the perfect numbers:" << endl;

 //check numbers from 1-1000
 for (i = 1; i <= 1000; i++)
 {
  sumOfFactors = 0;

  //look for the factors of a number
  for (j = 1; j < i; j++)
  {
   //check for factors and add them up
   if (0 == (i%j))
   {
    sumOfFactors += j;
   }
  }

  //if perfect number, print
  if (sumOfFactors == i)
  {
   cout << i << endl;
  }
 }
   
 getchar();

 return 0;
}

/*
Division without using / operator
Remainder without using % operator
*/
#include <iostream>

using namespace std;

int main(void)
{ 
 //variables
 int dividend, divisor, quotient, remainder;
 char stay;

 cout << "Input dividend: ";
 cin >> dividend;

 cout <<endl << "Input divisor: ";
 cin >> divisor;

 quotient = 0;

 // always subtract dividend with the divisor
 //until dividend is lesser than the divisor
 while (dividend >= divisor)
 {
  dividend -= divisor;
  //quotient = count every time subtraction is done
  quotient++;
 }
 
 cout << endl << "The qoutient = " << quotient << endl;

 //remainder = the remaining value after a series of substraction
 remainder = dividend;
 cout << "The remainder = " << remainder << endl;

 //wait for an input before exit 
 cin >> stay;

 return 0;
}

/*
Multiplication without using * operator
*/
#include <iostream>

using namespace std;

int main(void)
{
 //variables
 int number1, number2, product;
 char stay;

 cout << "Input first number: ";
 cin >> number1;

 cout << endl << "Input second number: ";
 cin >> number2;

 cout <<endl << number1 << " * " << number2 << " = ";

 product = 0;

 // choose either of the two numbers for the addition
 // choose the other number as a counter
 while (number2 > 0)
 {
  //add the number
  product += number1;

  //decrement counter
  number2--;
 }
 
 cout << product <<endl;
 
 //wait for an input before exit 
 cin >> stay;

 return 0;
}

/*
Basic Mathematics program
*/
#include <iostream>

using namespace std;

int main(void)
{
 //variables
 int number1, number2, sum, difference, product, quotient, remainder;
 char pause;

 cout << "Enter first number = ";
 cin >> number1;

 cout << "Enter second number = ";
 cin >> number2;

 sum = number1 + number2;
 product = number1 * number2;

 //consider first which number is bigger
 if (number1 > number2)
 {
  difference = number1 - number2;
  quotient = number1 / number2;
  remainder = number1 % number2;
 }
 else
 {
  difference = number2 - number1;
  quotient = number2 / number1;
  remainder = number2 % number1;
 }

 cout << endl 
  << "Addition = " << sum << endl
  << "Difference = " << difference << endl
  << "Product = " << product << endl
  << "Quotient = " << quotient << endl
  << "Remainder = " << remainder << endl;

 //don't close windows console yet
 cin >> pause;

 return 0;
}

/*
Addition and Multiplication of two numbers
*/
#include <iostream>

using namespace std;

int main(void)
{
 //variables
 int number1, number2, sum, product;
 char stay;

 cout << "Input first number: ";
 cin >> number1;

 cout << endl << "Input second number: ";
 cin >> number2;
 
 // add the two numbers
 sum = number1 + number2;
 
 cout << endl << "The sum is " << sum <<endl;

 // multiply the two numbers directly within cout
 cout << endl << "The product is " << number1 * number2 << endl;
 
 //let console wait for an input before exit 
 cin >> stay;

 return 0;
}